It is ridiculously easy to mock the GOP Senate caucus for its fecklessness in 2019. This was on display over the weekend. Bloomberg’s Mark Niquette wrote a story headlined “GOP Senators Exhale After Considering Crossing Trump on Tariffs,” which is about as 2019 as one can get. The story itself quotes lots of GOP senators praising President Trump for not imposing tariffs on Mexico and reaching a deal that, by reputable media accounts, contained no new concessions from that country. Niquette correctly observes that “crossing the president, whose popularity with Republican voters is very high, carries a definite risk for the party’s lawmakers, including facing primary challengers more aligned with Trump the next time they’re up for reelection.”

It is difficult to dispute the spinelessness of the GOP Senate caucus in the Age of Trump. This is best epitomized by Senate Majority Leader Mitch McConnell, who talked about being an “institutionalist” for the New York Times Magazine, but in the end sided with the president when he declared a national emergency and usurped the Senate’s constitutional authority to dictate federal spending. Before the midterms, senators like Bob Corker and Jeff Flake would occasionally criticize the president in blunt terms. Now, the closest thing that represents Trump dissent is Sen. Mitt Romney telling the Associated Press that he might not endorse Trump come 2020. Perhaps this reflects the fact that Trump has slightly more wiggle room with a 53-47 Senate majority than he did during his first two years in office.

Let’s agree that the GOP Senate has not covered itself in glory. It has by and large accepted the Faustian bargain of supporting the president in return for getting the things senators want - tax cuts and conservative justices. But “by and large” does not mean all the time, and it is worth considering that these senators do have some actual red lines. What makes these lines somewhat less visible is the fact that when they are crossed, the president usually retreats rather than forces a vote.

Some of these red lines are born out of past rivalries. For example, last month it was reported that the Trump White House would appoint Ken Cuccinelli to be an immigration czar at the Department of Homeland Security. At the time, The Washington Post’s Josh Dawsey and Nick Miroff noted, “he would face a difficult path to confirmation” because “Cuccinelli is deeply disliked by Senate Majority Leader Mitch McConnell.” This was due to Cuccinelli’s past endorsements of insurgents in GOP Senate primaries who flamed out in the general election.

Sure enough, last week Politico’s Burgess Everett and Eliana Johnson reported that “Some senators are still hoping to persuade Trump not to formally nominate or appoint Cuccinelli, but if the president goes through with it, the former Virginia attorney general likely will be either rejected or blocked from a floor vote entirely.” Their story contains on-the-record quotes from Sen. John Thune and John Cornyn that are dismissive of Cuccinelli’s chances, which is a pretty good indicator that he has no chance.

Is this an example of high-minded, principled behavior by the GOP Senate? No, it is not. But it is an example of the senators not complying with Trump’s whims on an issue central to the president, which is noteworthy.

Cuccinelli is simply the latest example of a Trump appointee facing a veto point in the GOP-controlled Senate. Earlier this year Trump wanted to appoint Stephen Moore and Herman Cain, two manifestly unqualified individuals, to serve on the Federal Reserve Board of Governors. In the end, both withdrew their names from consideration after it became clear that enough GOP senators would vote no, torpedoing their chances.

Part of the reason Republican senators have shown more backbone on this issue is that the Trump White House has been so manifestly incompetent at vetting its nominees. Politico’s Andrew Restuccia noted this last month:

“The Trump administration’s long-standing vetting problems have contributed to a surge in doomed nominees.

“In total, Trump has withdrawn 62 nominees since taking office, according to data provided to POLITICO by the Partnership for Public Service, a nonprofit that tracks federal vacancies. At this point in his presidency, Barack Obama had withdrawn 30 nominees. The figures include only people who were formally nominated, so Moore and others who took themselves out of consideration before their official paperwork was sent to the Senate aren’t counted.

“The Trump administration has struggled for years to adequately vet nominees, dating back to the presidential transition, when Trump filled his Cabinet with friends and associates with little regard for the rigor of the traditional government hiring process, according to transition officials.”

Even on the tariff issue, the Trump White House was feeling the heat from GOP senators. As noted last week, an awful lot of them publicly complained about the president’s addiction to tariffs. Sen. Charles Grassley keeps making noises about curbing the president’s powers to impose some tariffs. With businesses now starting to lobby to curtail the president’s powers on this issue, who knows what will happen?

The answer, unfortunately, is probably nothing. It remains the case that most GOP senators are rock solid in their support of Trump. Others, like Florida Sen. Marco Rubio, have found new and innovative ways to go back on their conservative principles to demonstrate fealty to the president.

Nonetheless, it would be wrong to describe the GOP senators as a rubber stamp. They have occasionally pushed back. Their strong desire to do so without casting votes does not make them uniquely craven. It makes them politicians.

Daniel W. Drezner is a professor of international politics at the Fletcher School of Law and Diplomacy at Tufts University.