Republican Senator Thom Tillis of North Carolina is making headlines after revealing what he considers the biggest mistake of his political career — and it involves one of President Donald Trump’s most prominent Cabinet members.
In his new memoir, How to Lose Friends and Antagonize Presidents, Tillis expresses serious regret over his decision to support Defense Secretary Pete Hegseth during a closely contested Senate confirmation vote in January 2025.
The outgoing Republican senator describes that decision as the “biggest regret” of his career, raising fresh questions about disagreements within the Republican Party and the challenges facing Trump’s administration.
The revelations come as Republicans prepare for the November midterm elections, when control of Congress will once again be decided by American voters.
Tillis Reconsiders His Support for Trump’s Defense Secretary
According to reporting from The Associated Press, Tillis details the difficult decision he faced when Hegseth’s nomination came before the Senate.
Before the confirmation vote, Hegseth faced allegations concerning his management practices, treatment of women, and alcohol consumption. Hegseth denied the allegations.
Tillis reportedly spent considerable time reviewing the accusations, communicating with White House officials, speaking with individuals familiar with Hegseth’s professional background, and questioning the nominee directly.
Despite his concerns, the North Carolina Republican ultimately concluded that he could not verify the most serious allegations.
He also acknowledged that he was reluctant to become the single Republican responsible for blocking one of Trump’s major Cabinet appointments.
On January 24, 2025, Tillis voted to confirm Hegseth. The Senate divided evenly, leaving Vice President JD Vance to cast the deciding vote in favor of confirmation.
That decision is now one Tillis says he wishes he had handled differently.
What Tillis Said About His Original Decision
At the time, Tillis publicly defended his support for Hegseth, emphasizing the nominee’s military experience and commitment to strengthening America’s armed forces.
Hegseth, a former Fox News personality, served in both Iraq and Afghanistan before entering the Trump administration.
Tillis initially argued that Hegseth’s firsthand military experience could help advance the president’s national security priorities.
In a statement issued following his January 2025 confirmation vote, Tillis expressed confidence that Hegseth would help modernize the military and support Trump’s “peace through strength” agenda.
However, his latest comments suggest that his assessment has changed considerably.
In his memoir, Tillis argues that some Republican lawmakers supported controversial administration decisions because they feared the political consequences of opposing the White House.
He suggests that concerns about reelection and maintaining political influence sometimes affected how lawmakers approached important decisions.
Those observations offer a revealing glimpse into the pressures facing Republicans during Trump’s second term.
Republican Senator Calls for Hegseth’s Removal
Tillis’s criticism of Hegseth has intensified over time.
In July 2025, the senator suggested that he might reach a different conclusion if Hegseth’s confirmation came before the Senate again. At that point, however, he maintained that he did not regret his original vote.
His position became significantly more critical in the following months.
In September 2026, Tillis publicly supported efforts to remove Hegseth from office, including the possibility of impeachment.
He also indicated that President Trump could resolve the situation more directly by appointing a replacement.
The senator’s comments represented a notable change from his earlier support for Hegseth and highlighted growing tensions between Tillis and senior members of the administration.
Nevertheless, Tillis’s position should not be confused with a broader Republican consensus. His criticism represents his own assessment, and his original confirmation vote helped secure an important victory for Trump’s administration.
Another Trump Cabinet Appointment Draws Regret
Hegseth is not the only administration official Tillis discusses critically in his book.
The North Carolina senator also questions his decision to support Robert F. Kennedy Jr. as secretary of Health and Human Services.
Tillis now believes he should have done more to prevent Kennedy’s confirmation.
In the memoir, he accepts personal responsibility for his vote while expressing dissatisfaction with Kennedy’s leadership of the department.
The criticism adds another dimension to Tillis’s evolving relationship with the Trump administration.
Although he initially supported several major Cabinet nominees, Tillis has increasingly questioned their performance and the administration’s approach to governing.
His remarks also underscore the responsibility senators carry when deciding whether presidential nominees should receive positions of considerable national importance.
Tillis Warns Republicans About the Midterm Elections
Beyond his criticism of individual Cabinet officials, Tillis offers a troubling prediction for Republicans heading into November.
The senator warns that the GOP could suffer significant electoral losses as it attempts to maintain and expand its congressional majorities.
His prediction reflects concerns about internal party disagreements, controversial policy decisions, and the political challenges facing Republicans during the second half of Trump’s term.
Tillis, who previously announced that he would not seek reelection, has become increasingly willing to criticize administration decisions without facing the same electoral considerations as colleagues seeking another term.
However, he stops short of placing all responsibility for the party’s difficulties on President Trump.
Instead, the senator directs much of his frustration toward the president’s advisers and administration officials.
In the memoir, Tillis makes clear that his disagreements are not necessarily personal grievances against Trump himself. Rather, he believes certain individuals surrounding the president have contributed to decisions he considers damaging.
What This Means for Trump and the Republican Party
Tillis’s public criticism highlights a persistent challenge for Republican leadership: maintaining party unity while allowing elected officials to independently evaluate administration policies and presidential appointments.
Trump continues to play a central role in shaping the Republican Party’s political direction. At the same time, disagreements over Cabinet leadership, federal spending, and national security have occasionally exposed divisions among GOP lawmakers.
For Tillis, the Hegseth confirmation has become a defining example of how difficult those decisions can be.
His memoir raises broader questions about congressional oversight, political loyalty, and whether senators should place greater emphasis on their independent judgment when reviewing presidential nominees.
As the November elections approach, Republican candidates will face the task of communicating their priorities to voters while addressing disagreements within their own party.
The Bottom Line: Senator Thom Tillis now considers his vote to confirm Pete Hegseth his greatest political regret. Although he remains critical of several Trump administration officials, he has made clear that his disagreements extend beyond the president himself.
Whether Tillis’s warnings prove accurate will become clearer after Americans cast their ballots in November. His comments nevertheless provide an unusually candid look at the internal debates shaping the Republican Party during Trump’s second administration.