2026 Midterm Election Watch | Toppling Dissenters Is Easy; Holding the States Is Hard: The Successes and Failures of Trump’s Endorsements

According to Ballotpedia’s July 10 tally and the results of Arizona’s July 21 primary elections, Donald Trump issued 307 primary endorsements during the 2026 midterm election cycle. Of the 234 contests that had been decided, Trump-endorsed candidates won 227 and lost only seven, producing a success rate of 97 percent—the highest on record.

An NPR analysis of more than 1,000 endorsements Trump has issued over the past decade indicates that his endorsement strategy has undergone a marked transformation. During the 2018 midterm elections, Trump issued his endorsements an average of seven weeks before the relevant primary. In 2026, the average lead time expanded to approximately seven months. Nearly 75 percent of his 2026 endorsements went to incumbents, compared with an overall proportion of roughly two-thirds since 2017. By intervening earlier, Trump has often deterred potential challengers from entering races, thereby directly increasing the probability that his preferred candidates will prevail.

I. The Successful Purge of Three Incumbent Dissenters

Behind Trump’s exceptionally high endorsement success rate, the most consequential development has been his successful removal of three incumbent members of Congress with whom he had longstanding political conflicts.

1. Bill Cassidy of Louisiana

Louisiana Senator Bill Cassidy received only approximately 25 percent of the vote in the May 16 primary, finishing third and failing to qualify for the runoff.

Cassidy’s conflict with Trump dates to 2021, when he became one of seven Republican senators who voted to convict Trump during his second impeachment trial. The relationship deteriorated further after Cassidy, serving as chair of the Senate Committee on Health, Education, Labor, and Pensions, or HELP Committee, criticized Secretary of Health and Human Services Robert F. Kennedy Jr. during confirmation hearings and obstructed Trump’s nomination of Casey Means for surgeon general.

Following Cassidy’s defeat, Trump celebrated on Truth Social:

“His disloyalty to the person who helped get him elected is now legendary. So glad to see his political career come to an end.”

Cassidy responded indirectly in his concession speech:

“No tantrums, no whining, and no claims that the election was stolen.”

Cassidy will continue to chair the HELP Committee until his Senate term expires in January 2027. His successor as committee chair has not yet been determined. Should Republicans retain their Senate majority, Senator Rand Paul would be next in line under the chamber’s seniority system. Paul, however, currently chairs the Senate Homeland Security and Governmental Affairs Committee, and it remains unclear whether he would be willing to relinquish that position.

Senator Roger Marshall has also expressed interest in the HELP chairmanship, describing the opportunity to lead the committee as “an honor for which I have prepared my entire life.” Both Paul and Marshall are physicians, and both support the “Make America Healthy Again,” or MAHA, movement. Regardless of which senator ultimately assumes the chairmanship, the HELP Committee is likely to shift substantially toward supporting Kennedy’s public-health agenda. Its leadership will therefore constitute an important variable during the final two years of Trump’s presidency.

2. John Cornyn of Texas

Texas Senator John Cornyn lost the May 26 runoff to Trump-backed Attorney General Ken Paxton by a decisive margin of 36.2 percent to 63.8 percent, bringing Cornyn’s 24-year Senate career to an end.

The conflict between Cornyn and Trump developed along three principal dimensions.

First, Cornyn played a leading role in negotiating the bipartisan gun-safety legislation enacted after the 2022 school shooting in Uvalde, Texas. Trump condemned the legislation as “the first step in the radical left’s movement to take your guns away.”

Second, Cornyn publicly declared in 2023 that “the Republican Party needs new leadership” and that “Trump’s era is over.” Trump responded by comparing him with Senator Mitt Romney and asking:

“Who is the worse senator, ‘Wooden’ Cornyn or ‘Loser’ Romney?”

Third, Cornyn delayed endorsing Trump during the 2024 Republican presidential primary and did not announce his support until after the New Hampshire primary results had made Trump’s nomination increasingly inevitable.

Seeking to repair his relationship with Trump before the 2026 runoff, Cornyn made several major concessions. He published an opinion article supporting the abolition of the Senate filibuster to facilitate passage of the Safeguard American Voter Eligibility Act, or SAVE Act, reversing his longstanding defense of the procedural rule. He also introduced legislation proposing that an interstate highway running through Texas to the Canadian border be renamed the “Trump 47 Interstate.”

These overtures proved ineffective. Trump had become dissatisfied with the hesitation of Senate Republicans over funding for the White House ballroom and ultimately endorsed Paxton one week before the runoff. In his concession speech, Cornyn pledged to support the Republican nominee in the general election.

3. Thomas Massie of Kentucky

Kentucky Representative Thomas Massie lost the May 19 Republican primary to Trump-backed candidate Ed Gallrein by approximately ten percentage points.

Massie, known for his noninterventionist foreign-policy views and fiscal conservatism, had clashed with Trump across several policy domains. He voted against Trump’s signature tax legislation on the grounds that it would exacerbate the national debt. He played a leading role in advancing legislation requiring greater transparency concerning the Jeffrey Epstein files, provoking opposition from the White House. He publicly opposed joint US-Israeli military operations against Iran and voted against unconditional military assistance to Israel.

Trump repeatedly attacked Massie on Truth Social, describing him as “the worst congressman in the long and glorious history of the Republican Party” and as “a lightweight loser who only knows how to vote no.”

Trump personally recruited Gallrein, a former Navy SEAL and fifth-generation Kentucky farmer, to challenge Massie. His political operation also established MAGA KY, a super political action committee dedicated specifically to defeating Massie and managed by Trump adviser Chris LaCivita.

Paul Singer, a major pro-Israel Republican donor, contributed US$1 million to MAGA KY, while a super PAC associated with the Adelson family contributed an additional US$750,000. On the day before the primary, Secretary of Defense Pete Hegseth personally traveled to the district to campaign for Gallrein. Total advertising expenditures in the contest reached US$37 million, setting a record for a US House primary.

Massie did not become politically inactive after his defeat. On July 15, he introduced an amendment to the State Department appropriations legislation that would have eliminated the full US$3.3 billion in annual US military assistance to Israel. The amendment failed by a vote of 104 to 314. Massie was the only one of the House’s 215 Republicans to support it, joined by 103 Democrats.

Massie also worked with Democratic Representative Ro Khanna to introduce an amendment seeking to remove Section 219 of the National Defense Authorization Act, which would further integrate US-Israeli military-technology cooperation.

For a defeated representative approaching the end of his congressional service, Massie’s continued activism on Israel policy constituted both a final rebuke to Trump and a source of legislative leverage for critics of Israel within the Democratic Party. Preventing precisely this form of cross-party political coordination was a central reason Trump and pro-Israel donors spent US$37 million to remove him from Congress.

Traditionally, incumbent lawmakers have relied on records of securing federal appropriations and extensive networks of constituent services to resist primary challenges. Within the information environment dominated by Trump, however, loyalty has replaced legislative performance as the principal criterion by which Republican primary voters evaluate candidates.

Cassidy’s expertise in public health, Cornyn’s extensive legislative experience, and Massie’s record of constitutional-conservative voting all failed to generate sufficient electoral support. Paradoxically, after losing their primaries, all three became more outspoken critics of Trump’s agenda during the final months of their terms.

II. Repeated Failures in Gubernatorial and State-Level Elections

All seven of Trump’s endorsement defeats occurred at the state level.

According to Ballotpedia’s July 8 data, the defeated candidates included Iowa gubernatorial candidate Randy Feenstra, South Carolina gubernatorial candidate Pamela Evette, Georgia gubernatorial candidate Burt Jones, North Carolina Senate President Pro Tempore Phil Berger, Indiana state senator Bruce Borders, Indiana challenger Brenda Wilson, and Texas Agriculture Commissioner Sid Miller.

The Washington Examiner characterized Trump’s three gubernatorial-primary defeats as “rare blemishes” on his endorsement record. The contests nevertheless shared a common pattern: where wealthy candidates were able to finance their own campaigns on a massive scale, or where deeply rooted local competitors possessed strong independent political organizations, the appeal of Trump’s national brand was insufficient to overcome state-specific factors.

1. Georgia

The Georgia gubernatorial primary represented Trump’s most expensive endorsement defeat of the 2026 election cycle.

Trump endorsed Lieutenant Governor Burt Jones approximately nine months before the primary. The endorsement was based largely on Jones’s early and consistent loyalty: he was the first member of the Georgia legislature to endorse Trump and supported Trump’s presidential campaigns in 2016, 2020, and 2024.

Healthcare-industry billionaire Rick Jackson, however, invested more than US$100 million of his personal wealth in the campaign. In the June 16 runoff, Jackson defeated Jones by approximately 53 percent to 47 percent. A Republican strategist told Politico that Jackson’s financial resources had “sucked all the political oxygen out of the race.”

Jackson presented himself during the campaign as a strong Trump supporter, although his political-donation history included contributions to establishment Republicans such as Mitt Romney, the Bush family, Nikki Haley, and Liz Cheney.

After the election, Trump congratulated Jackson on Truth Social, stating that “Rick Jackson ran a great Trump-style campaign—very smart.” The statement represented an effort to reinterpret an endorsement defeat as an indirect political victory.

Jackson will face former Atlanta mayor Keisha Lance Bottoms in the general election. Bottoms won the Democratic primary with approximately 56 percent of the vote and carried 158 of Georgia’s 159 counties. The primary also marked the first time since 2006 that Democratic primary turnout in Georgia exceeded Republican turnout.

The RealClearPolitics polling average showed Bottoms leading by approximately 3.7 percentage points. Surveys conducted by Fox News, Wick Research, State Navigate, and other organizations similarly placed her ahead.

The Georgia governorship carries particular political significance in the 2026 midterm elections. Following the 2020 presidential election, Trump repeatedly alleged electoral fraud in the state. He pressured then-secretary of state Brad Raffensperger to “find” the number of votes necessary to reverse the result and repeatedly denounced Governor Brian Kemp as a “Republican traitor” after Kemp refused to cooperate.

These disputes continue to shape Georgia’s political environment. Should Bottoms win in November, she would become the state’s first Democratic governor since 1998. Her victory would also directly affect the administration of Georgia’s electoral infrastructure ahead of the 2028 presidential election.

2. Iowa

The Iowa gubernatorial primary constituted the first direct confrontation between Trump’s MAGA coalition and Kennedy’s MAHA movement over agricultural policy.

Four days before the June 2 primary, Trump endorsed Representative Randy Feenstra, describing him as “MAGA from beginning to end.” Businessman Zach Lahn, who had aligned himself with the MAHA movement, nevertheless defeated Feenstra by 37.8 percent to 37 percent—a margin of less than one percentage point.

The principal disagreement between the candidates concerned agricultural chemicals.

Feenstra defended the use of pesticides, arguing that they had been thoroughly evaluated by regulatory agencies. Lahn adopted the opposite position. He opposed legal-liability protections for pesticide manufacturers and publicly criticized Trump’s executive order increasing glyphosate production.

Lahn also associated the use of agricultural chemicals with Iowa’s rising cancer incidence and elevated nitrate levels in Des Moines drinking water. In his victory speech, he declared:

“I am going to war against Big Agriculture. I will break its monopoly and fight for fair treatment for Iowa farmers.”

Tony Lyons, chair of the MAHA Political Action Committee, described the result as “a signal that supporting pesticides is not the same as supporting farmers.”

Trump subsequently blamed the quality of the information he had received:

“If I had been given the correct information—and I don’t think I was—I might have endorsed the other person.”

He even claimed that “the person running against Feenstra was completely aligned with Trump.”

Lahn will face Democrat Rob Sand in the general election. Sand, the Iowa state auditor, is currently the only Democrat holding statewide elected office in Iowa. He faced no opponent in the Democratic primary and entered the general election with US$18.3 million in cash on hand, giving him one of the largest financial advantages of any gubernatorial candidate in the country.

The RealClearPolitics polling average showed Sand leading by approximately five percentage points, an advantage corroborated by surveys from The New York Times/Siena College and Fox News.

Republicans have controlled the Iowa governorship since 2010 and have maintained a state-government trifecta since 2017. Should Sand prevail, he would become Iowa’s first Democratic governor since Chet Culver was elected in 2006, ending unified Republican control of the state government.

On July 20, Cook Political Report founder Charlie Cook stated that Iowa was behaving “differently” from other Republican-leaning states and that the governorship was “very likely to flip.” Republican defensive pressures have been intensified by the state’s exposure to tariff-related economic disruption and by the decisions of Governor Kim Reynolds and Senator Joni Ernst not to seek reelection.

3. South Carolina

Following the South Carolina gubernatorial primary, Trump made a rare adjustment to his endorsement strategy.

Trump initially gave Lieutenant Governor Pamela Evette his “complete and total endorsement.” Evette nevertheless received less than 30 percent of the vote in the June 9 primary, narrowly finishing first by approximately three percentage points over state attorney general Alan Wilson.

After consecutive endorsement defeats in Iowa and Georgia, Trump issued a dual endorsement before the June 23 runoff:

“I cannot hurt one of them by endorsing only the other, so I am endorsing … Pam Evette and Alan Wilson!”

Wilson ultimately won the runoff by 68.6 percent to 31.4 percent, a margin approaching two to one.

Although Republicans remain overwhelmingly favored to retain the South Carolina governorship, the state’s broader political environment changed abruptly in July. Senator Lindsey Graham died of sudden cardiac arrest on July 12 at the age of 71.

At Trump’s suggestion, Governor Henry McMaster appointed Graham’s sister, Darline Graham Nordone, to fill the Senate seat until the expiration of the current term in January 2027. Nordone was sworn into office on July 14, becoming the first female senator in South Carolina history.

On July 18, Trump endorsed Nordone in the August 11 Republican special primary for a full six-year Senate term. On July 21, she confirmed her candidacy on Fox News, stating, “I have made my decision. I am in.”

Nordone will face several Republican challengers, including Representatives Ralph Norman and Russell Fry. According to FITSNews, Evette has also been considering entering the special primary for Graham’s former Senate seat.

4. Oklahoma

The Oklahoma gubernatorial contest represents Trump’s only remaining opportunity to reverse one of his 2026 gubernatorial setbacks.

Trump endorsed former state senator Mike Mazzei, describing him as a “MAGA warrior.” In the June 16 primary, Mazzei finished second with 25.5 percent of the vote, only 0.4 percentage points behind state attorney general Gentner Drummond, who received 25.9 percent. The two candidates will compete in an August 25 runoff.

The central policy dispute in the runoff concerns a proposed primary-aluminum project in Inola, Oklahoma. Mazzei supports the project, while Drummond opposes it on environmental and infrastructure grounds.

In mid-July, Trump released a one-minute campaign video emphasizing Mazzei’s support for the aluminum project and attacking Drummond as a “RINO”—a “Republican in Name Only.” The criticism echoed Trump’s earlier attacks on outgoing Governor Kevin Stitt, whom he had also called a RINO during a dispute involving the National Governors Association.

Mazzei declined invitations to participate in televised debates organized by the nonprofit news outlet NonDoc and KSWO television. He agreed to participate in only one televised debate and three candidate forums.

The Republican runoff winner will face Democratic nominee Cyndi Munson, the former minority leader of the Oklahoma House of Representatives. Munson, the first Asian American woman elected to the Oklahoma legislature, won the Democratic primary with 75.1 percent of the vote.

III. Issues for Further Observation

1. The August 25 Oklahoma Runoff

Mazzei trailed Drummond by only 0.4 percentage points in the initial primary. Whether Trump’s campaign video and continued intervention can reverse the result in the runoff will provide the final opportunity for Trump to restore the credibility of his gubernatorial endorsements during this election cycle.

2. The November Gubernatorial Elections in Georgia and Iowa

Georgia has not elected a Democratic governor since 1998, while Iowa has not done so since 2006. Current RealClearPolitics polling averages show Bottoms leading in Georgia by approximately 3.7 percentage points and Sand leading in Iowa by approximately five points. Both contests therefore currently fall within a Democratic-advantage range.

Should both states produce Democratic governors despite their broader Republican orientation, the resulting “red-state, blue-government” configuration would impose substantive constraints on the federal administration.

Democratic governors could decline to cooperate with federal immigration-enforcement initiatives, veto restrictive voting legislation passed by Republican state legislatures, shape decisions regarding Medicaid expansion, and influence the redistricting process following the 2030 census. These powers could, in turn, affect the partisan configuration of both states for the following decade.

3. The Potential National Expansion of the MAGA–MAHA Divide

Lahn’s victory in Iowa represents the first major electoral success for a distinctly MAHA-oriented candidate in a Republican primary.

Future analysis should examine whether the mobilizing power of agricultural-chemical issues in Iowa can be replicated in other agricultural states. The extent to which disputes over pesticides, corporate liability, food safety, rural health, and agricultural consolidation divide MAGA and MAHA constituencies may become a critical variable not only in the 2026 midterm elections but also in the 2028 presidential campaign.