On matters of policy, there’s little daylight between Democrats like Christopher S. Murphy of Connecticut and his Senate colleagues in neighboring Massachusetts, Edward J. Markey and Elizabeth Warren.

But presidential support voting in 2020 reveals that there is a big difference in how they see their roles as senators in opposition to a president of the other party.

In a year in which presidential support voting in the Senate dealt mainly with how senators felt about President Donald Trump’s nominees to federal judgeships and executive branch jobs, the split was between institutionalists like Murphy, who believe presidents should generally get their picks, and the Democratic resistance, which viewed Trump as such a threat to American governance that they sought to block him at every turn.

The difference is striking. Murphy backed Trump’s position on Senate votes 47 percent of the time, while Markey and Warren did on 19 percent, according to CQ Roll Call’s analysis of presidential support voting in 2020.

It was all about nominations. Of the 114 votes on which Trump took a position in 2020, 93 were in support of his nominees. This was a function both of Trump’s disinterest in policy matters — compared to his predecessors, he took few policy positions throughout his presidency — but also then-Senate Majority Leader Mitch McConnell’s desire to stock the judiciary with conservative judges. This became McConnell’s overriding priority after Democrats won the House majority in the 2018 election and the possibility of conservative legislation evaporated.

In his four years in office, Trump nominees received more floor votes (433), than did the nominees of Barack Obama (384), George W. Bush (245) or Bill Clinton (104) over their entire eight-year terms.

This was a function of McConnell’s priorities, but also of Democratic resistance. Previous presidents could count on uncontroversial nominees sailing to confirmation by unanimous consent or voice vote, while Trump could not. 

Thus far, 2021 has seen a return to something approaching the pre-Trump norm, with 13 top Biden nominees confirmed through Tuesday, 10 with more than half of Republican senators in favor. Strong opposition is expected for some of those who remain, however, including Health and Human Services nominee Xavier Becerra and Interior nominee Deb Haaland.

Former Senate Majority Leader Harry Reid’s 2013 decision to allow a simple majority to confirm nominees, lowering the threshold from 60 votes previously, has fundamentally shifted the Senate’s workload when the same party controls the chamber and the White House and presidential support voting along with it. Presidential support votes are ones on which the president has taken a clear position and that is the case, by definition, for nominees to judgeships and federal jobs.

Trump’s nominees accounted for more than 80 percent of his Senate positions in each of his four years. In every other year since 1988 when CQ began parsing Senate presidential votes as either nomination or policy votes, that percentage was lower, except for 2014 when Obama and Reid used the rule change to push through 124 nominees before the GOP took the Senate majority in that year’s election.

The slant toward nominations in 2020 also had the effect of driving up Republican senators’ support for the president, as they almost universally backed his picks. They backed Trump 90 percent of the time overall — differences between Trump and Republican senators over the president’s authority to attack Iran and the annual defense authorization bill brought that number down — and 93 percent over his presidency, weighting each year equally. By comparison, Republican senators backed President George W. Bush 86 percent of the time during his eight years as president.

Democratic senators’ votes demonstrate the opposite effect. They backed Trump an average of 34 percent of the time in 2020 and 36 percent over his four years, counting each year equally. By contrast, their average support score for Bush’s eight years was 51 percent.

In the Senate, the minority party’s willingness to cooperate with a president of the other party has badly eroded in just the last generation. In 2000, the last year of Bill Clinton’s presidency, the gap in the presidential support scores between the Republican senator most willing to back the president, Olympia J. Snowe of Maine at 72 percent, and the least supportive GOP senator, John McCain of Arizona, was a mere 18 points.

That gap grew in George W. Bush’s and Obama’s presidencies and became a yawning canyon in Trump’s. The difference between the Democratic senator most supportive of Trump in 2020, Joe Manchin III of West Virginia, and the least, Warren, was 48 points, with Manchin backing Trump’s position 67 percent of the time.

These differences, however, were almost entirely symbolic with Republicans in charge of the chamber and only a simple majority required to confirm Trump’s picks. Republicans did not need Democratic votes.

Democrats narrowly control the Senate now, after they secured a 50-50 tie by winning two Georgia runoffs in January. They can approve President Joe Biden’s nominees without GOP support if they stick together. But the next time a president faces a Senate run by the opposite party, as Biden might after the 2022 midterms, these philosophical changes in how the opposition party views presidential nominees will matter a great deal.

In 2020, Warren and Markey cast resistance votes against numerous Trump picks, from Michael George DeSombre, who was confirmed as ambassador to Thailand by a vote of 91-7 in January, to Fernando L. Aenlle-Rocha, who won a federal district court judgeship in California in a 80-8 vote in December. Occasionally, Murphy joined a minority of his caucus in voting “yes” on Trump picks, as he did in December in voting to confirm J. Philip Calabrese to a district court judgeship in Ohio and Liam P. Hardy to a judgeship on the U.S. Court of Appeals for the Armed Forces.

On 2020 policy votes, meanwhile, Democrats rarely sided with the president on matters that split the parties. They were almost all with him on the bipartisan bills, like the legislation implementing January’s U.S.-Canada-Mexico trade agreement and last March’s coronavirus relief package. But they were in lockstep seeking to require Trump to get Congress’ approval before attacking Iran and in backing a 2021 defense authorization bill that ordered the renaming of military bases honoring Confederates, which Trump opposed.

CQ Roll Call editors select presidential support votes each year based on clear statements by the president or authorized spokespersons.