In a high-stakes Senate vote Tuesday, Elbridge Colby was confirmed as Under Secretary for Policy at the Department of Defense by a narrow 54-45 margin — but not before a very public rebuke from one of the most powerful figures in Republican politics: Mitch McConnell.

The Kentucky senator, long known for his hawkish foreign policy stance and frequent clashes with the Trump wing of the GOP, was the only Republican to vote against Colby’s nomination. The move drew immediate backlash from America First leaders, with Vice President JD Vance blasting McConnell’s vote as “one of the great acts of political pettiness I’ve ever seen.”

Colby, a seasoned defense strategist and former deputy assistant secretary of defense under Trump, is widely regarded as a principal architect of the 2018 National Defense Strategy, which pivoted U.S. military focus toward confronting China in the Indo-Pacific. He now becomes the third-ranking official at the Pentagon under Secretary Pete Hegseth, tasked with translating President Trump’s America First vision into daily policy.

Despite Colby’s strong GOP support, McConnell accused him of embracing what he called an “Obama-era a la carte geostrategy.” In a lengthy statement, the 83-year-old senator warned that Colby’s approach — prioritizing the Indo-Pacific over Europe and the Middle East — would weaken America’s alliances and embolden its enemies.

“Make no mistake,” McConnell said, “America will not be made great again by those who are content to manage our decline.”

McConnell’s resistance to Colby came as no surprise to close observers of the intra-party feud over Trump-era foreign policy. The senator also voted against the confirmations of Defense Secretary Hegseth and Director of National Intelligence Tulsi Gabbard — all core figures reshaping America’s global posture under Trump 2.0.

But McConnell stood alone this time, as several Senate Democrats broke ranks with their party to support Colby, including Sen. Jack Reed of Rhode Island, who chairs the Armed Services Committee, as well as Sens. Mark Kelly (AZ) and Elissa Slotkin (MI). Their votes ensured Colby’s confirmation, even without unanimous Republican backing.

Colby’s critics, like McConnell, are concerned about his skepticism toward U.S. entanglements in Europe and the Middle East. But Colby has argued repeatedly that the U.S. must focus its limited resources on confronting the primary threat: China.

During his March 4 confirmation hearing, Colby pulled no punches: “Peace and the protection of American interests in the world cannot be assumed,” he said. “There is a real risk of major war, and we cannot afford to lose one.”

He reaffirmed his commitment to executing Trump’s doctrine of “peace through strength” and defended his belief that stretching U.S. resources across endless global commitments leaves the country vulnerable where it matters most.

On Iran, Colby has been more nuanced than some hawks would prefer. In 2023, he warned that any attempt to destroy Iran’s nuclear program would be “very, very demanding and consuming.” Nevertheless, when pressed by Sen. Tom Cotton (R-AR) during his hearing, Colby labeled a nuclear-armed Iran an “existential threat” to the United States.

Colby’s confirmation is a clear victory for Trump’s national security vision, and it cements a growing realignment within the Republican Party. The old guard — led by McConnell — remains wedded to a globalist foreign policy built around sprawling commitments and military adventurism. But the new Trump-led coalition is focused on strategic prioritization, defense of the homeland, and disengagement from forever wars.

The former Senate majority leader’s isolated “no” vote is symbolic of just how far the party has moved beyond his influence.

As one Trump adviser put it after the vote: “Mitch is stuck in 2005. Bridge Colby is building the future.”

With Colby now confirmed and a growing list of Trump-aligned national security officials in place, expect a major overhaul of Pentagon priorities — and more fireworks between America First conservatives and the remnants of the old GOP establishment.