GOP senators are breaking ranks to challenge Defense Secretary Pete Hegseth's handling of the U.S.-Iran war, citing ballooning costs, forced retirements of senior commanders, and a conflict that has far outlasted early projections.
Sen. Thom Tillis of North Carolina delivered the sharpest public rebuke yet from a Republican lawmaker, telling The Hill that Hegseth has lost his support entirely. Tillis, who recently announced he will not seek reelection, accused the Defense Secretary of pushing out top military leaders while lacking the organizational experience to run the Pentagon.
"I don't have any confidence in him anymore," Tillis said.
"I think he's got a massive insecurity complex, he has a lack of experience in large organizations, he micromanages too much. He's lost my confidence."
Tillis is not alone. At least two other Republican senators, speaking on background, described growing alarm both on Capitol Hill and inside the Pentagon itself. One senator close to defense policymakers said the unease runs deep within the building Hegseth leads.
"I have heard out of the Pentagon that there's a loss of confidence, within the Pentagon. And of course then everyone here on the Hill hears those same concerns."
The criticism marks a significant shift. Senate Republicans confirmed Hegseth and have largely deferred to the White House on defense matters. But nearly five months into a war that President Trump projected in early March would last only four or five weeks, that deference is fraying, and the reasons are stacking up.
Hegseth appeared before the Senate Appropriations Committee last week to make the case for emergency defense funding. He told lawmakers the war had cost $37.5 billion. Independent analysts at Moody Analytics put the figure at $132 billion or more, roughly three and a half times the secretary's number.
That gap drew pointed questions from committee chair Susan Collins of Maine, who pressed Hegseth on both the cost discrepancy and the administration's broader strategy. Collins said after the hearing that she wanted "more information" from the administration on "the strategy and endgame for the war."
"I thought the hearing yesterday was somewhat helpful, but questions remain."
Sen. Joni Ernst of Iowa, who sits on the Armed Services Committee, echoed that concern. Ernst said lawmakers across the conference are troubled by what they see as a lack of clarity on spending and strategy, even after Hegseth's testimony.
"Collectively those of us in Congress are worried about the costs associated with the Department of War and the transparency. I think... why they've asked him to come to the Hill and present the numbers, and I still don't know that there's a lot of clarity on that."
The cost debate carries immediate legislative consequences. The House approved a budgetary framework last week that includes $73 billion for the Pentagon and U.S. intelligence agencies, part of a $95 billion reconciliation package, the special budgetary process that allows the Senate to pass spending with a simple majority, bypassing a Democratic filibuster. Trump has demanded the military funding move through that track.
But Senate Republicans warn they do not yet have enough votes within their own conference to pass it. Hegseth's controversial personnel decisions and the unresolved questions about war costs are making it harder to rally reluctant members before the August recess.
Beyond the budget numbers, senators are alarmed by Hegseth's treatment of the military's senior leadership. Chris Donahue, the top U.S. Army commander in Europe, was forced into retirement earlier this month. His departure is part of a broader pattern that critics say has hollowed out experienced leadership at a moment when the country is at war.
Collins called the removals "deeply troubling" during the Appropriations Committee hearing.
"These are men and women who volunteered to serve our country and swore an oath to support and defend our Constitution."
Tillis went further, describing internal Pentagon dynamics in blunt terms. He said Hegseth's management style has created friction with service secretaries and undermined the people best positioned to win the war.
"Everybody knows about some of the Game of Thrones stuff going on with some of the other service secretaries and Hegseth. It seems like he wants to run the whole place."
Tillis argued that effective leadership requires surrounding yourself with people who have deeper expertise, and that Hegseth is doing the opposite.
"When you're a leader, you better d*** sure have people smarter than you in the room. You're supposed to be air traffic control for all these brilliant people and he's undermining the DOD's success by undermining these brilliant people who spent their career in uniform."
Hegseth has also drawn scrutiny for removing officers from Navy promotion lists, part of his effort to reshape the military's leadership culture. Those moves generated debate even before the Iran conflict began. Now, with a shooting war underway and senior commanders being pushed out, the personnel decisions carry a different weight.
The strategic picture has darkened since February, when Iran closed the Strait of Hormuz, the narrow waterway through which a massive share of the world's oil supply passes. Oil and gas prices have risen dramatically in the months since. The closure remains in effect, and Iran shows no sign of reopening it voluntarily.
In recent days, the conflict expanded further. Iranian-backed Houthi militants began targeting Saudi oil shipments in the Red Sea, opening a second front near the Bab el-Mandeb Strait, another critical chokepoint for global shipping. Iran has also struck neighboring allies including Jordan, Kuwait, and Saudi Arabia.
A second Republican senator, speaking anonymously, acknowledged the administration failed to anticipate how far Iran would go.
"I think there's a sense it's taken longer than what we thought and that maybe our strategy didn't factor in the Strait of Hormuz or [Iran's] ability to be willing to hit their neighbors. I think there was some miscalculations maybe."
Tillis made the same point on the record. He said the administration should have foreseen Iran's ability to expand the conflict to the Bab el-Mandeb Strait, and that the failure to plan for that scenario reflects a broader leadership deficit at the Pentagon.
Sen. Shelley Moore Capito of West Virginia, in an interview with NewsNation, pointed to the political cost at home. "I do think that the American public's growing weary," she said. That weariness, driven by rising energy prices and a conflict with no visible endpoint, is filtering into Capitol Hill conversations about whether the current approach can hold.
Not every Republican critic wants Hegseth gone. Some, particularly the conference's defense hawks, are directing their frustration at the pace and scale of military operations rather than at the secretary personally. Senate Armed Services Committee Chair Roger Wicker of Mississippi has urged President Trump to "finish the job" by stepping up the intensity of strikes against Iran.
Sen. John Cornyn of Texas framed the problem in terms familiar to conservatives who have watched previous administrations get bogged down in prolonged conflicts. Cornyn argued the U.S. has the military capability to force Iran's hand, but only if it acts decisively rather than escalating gradually.
"The problem of endless wars, in my view, is gradual escalation. Until then, you are stuck and there is no way out other than just sort of capitulation. So I think a decisive outcome by opening the Strait of Hormuz should be the goal."
"If anybody can do it, the United States can," Cornyn added. His confidence in American military power was clear. His confidence in the current Pentagon leadership was not.
The administration's challenges extend beyond strategy. Sen. Mitch McConnell of Kentucky has not voted since June 11 due to a health issue, and his absence complicates the math on the $73 billion military spending package. With the August recess approaching and the reconciliation vote still short of the support it needs, every Republican holdout matters. This is not the first time the Trump administration has faced turbulence among senior officials, but the stakes in a wartime cabinet are considerably higher.
Tillis suggested more of his colleagues are closer to speaking out than the current public head count suggests. "I think there are other people that are probably one decision or another" away from openly criticizing the Pentagon's leadership, he said.
The Hill reached out to the Department of Defense for comment. No response was included in its reporting. Meanwhile, broader questions about cabinet officials under pressure continue to shadow the administration across multiple agencies.
The picture facing Senate Republicans is uncomfortable. A war projected to last weeks has stretched to nearly five months. The Strait of Hormuz remains closed. Energy prices keep climbing. The conflict has spread to the Red Sea. Iran has struck American allies. The Pentagon's own cost estimate is a fraction of what independent analysts calculate. And the secretary running it all is losing support inside his own building and on Capitol Hill.
None of this means the mission itself is wrong. Reopening the Strait of Hormuz and checking Iran's aggression are goals most Republicans share. But goals require competent execution, honest accounting, and leaders who keep their best people in the room, not ones who push them out the door.
Wars test institutions. This one is testing whether the Pentagon has the leadership it needs, and whether the Senate will keep pretending the answer is yes.