John Thune, the new Mitch McConnell

Donald Trump has won the public approval of virtually every Republican currently holding federal office. Privately, however, at least one bastion of mild Republican resistance to Trump’s rise to power remains: the Senate Republican Conference.

Republican senators demonstrated that defiance today by electing Sen. John Thune of South Dakota as majority leader and soundly rejecting the candidate Trump’s allies favored for the post, Sen. Rick Scott of Florida. Thune, a 63-year-old in his fourth term, most recently served as a top lieutenant to Sen. Mitch McConnell, the longtime Republican leader whose relationship with Trump was notoriously difficult. Like McConnell, Thune criticized Trump’s role in inciting the insurrection at the Capitol on January 6, 2021, calling the former president’s actions “inexcusable.” He has since tried to repair the relationship in the hope that Trump would not try to thwart his bid to replace McConnell.

Now Thune’s partnership with Trump will determine how many of the president-elect’s nominees win confirmation and how much of his legislative agenda can pass Congress. Thune will have a larger Republican majority – the GOP will have 53 seats in January to the Democrats’ 47 – than the party had during Trump’s first term. But three of those Senate Republicans — Susan Collins of Maine, Lisa Murkowski of Alaska and Bill Cassidy of Louisiana — voted to convict and remove Trump from office after Jan. 6.

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The tests will begin immediately. Will Republicans confirm Trump’s choice of Pete Hegseth, a military veteran and Fox News host with no experience in government, as defense secretary? Or Rep. Matt Gaetz of Florida as attorney general? The potential nominations of Robert F. Kennedy Jr. and Kash Patel for leadership positions could also force Thune to decide how much deference to show the new president.

A GOP leader’s dislike of Trump doesn’t always lead to a legislative conflict. McConnell was unsparing in his criticism of Trump after January 6; He told his biographer Michael Tackett that Trump was “a scumbag” and that the attack on the Capitol showed his “total unfitness for office.” But as majority leader, McConnell rarely opposed Trump, blocked few nominees and ensured that the president could reshape the federal judiciary and Supreme Court. He voted to acquit Trump of his second impeachment trial, a decision that helped enable Trump’s political comeback.

Thune is likely to be even more forthcoming as Trump prepares to assume the presidency again. “This Republican team is united,” Thune told reporters after defeating Scott and Sen. John Cornyn of Texas in the leadership election. “We have a mandate from the American people to not only clean up the mess left behind by the Biden-Harris-Schumer agenda, but also to implement President Trump’s priorities.” He has so far signaled his support for Trump’s candidate – although the selection by Gaetz has not yet been announced – and promised to overcome Democratic opposition to her confirmation.

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But if Thune is no longer a Trump critic, he is no longer a loyalist either. He was socially and financially conservative and began his political rise when most Republicans were still loyal to Ronald Reagan’s legacy. Thune first won his Senate seat in 2004, defeating then-Democratic leader Tom Daschle, and was considered a possible presidential candidate. But instead he devoted himself to the Senate, and it took years before he sought to succeed McConnell. During his press conference today, Thune reiterated his commitment to maintaining the Senate’s 60-vote threshold to overcome a legislative filibuster – a McConnell priority that Trump frequently complained about during his first term. He also declined to immediately agree to Trump’s demand that the Senate allow him to install his nominees when Congress is not in session.

Thune’s main (if friendly) rival has long been Cornyn, who preceded Thune as the party’s second-ranking Senate leader. But the Trump wing distrusted both Johns and wanted Rick Scott, who had led the GOP campaign committee before unsuccessfully challenging McConnell for party leader after the 2022 midterm elections. Scott received several public endorsements from Trump loyalists in the week since the election. What’s notable, however, is that the former president declined to comment on the race, perhaps not wanting to spend his political capital on an underdog who would likely lose.

Had the vote been public, Scott might not have been such a strong candidate, and a loud pressure campaign led by Trump could have surpassed him. But senators choose their leaders by secret ballot, and a majority of Republicans seized the opportunity to choose the candidate in Thune who had the fewest ties to the new president. Fortunately for Trump, this vote will likely be the last major vote they can hold privately for a while.