The collapse Wednesday of Andrew Puzder’s nomination as US secretary of labor might turn out to be a historical footnote — or it might mark a welcome turning point in the new Trump administration. Hopefully, it’s a sign that the Republican Senate is waking up to its responsibility to act as a check on an administration that’s shown nothing but incompetence as it staggers through its first month.

Puzder, a fast-food baron, withdrew from consideration after Republican senators made it clear to the White House that he lacked the votes needed for confirmation. He’s the first, and so far only, Trump nominee turned aside by the Senate. Previously, the Republican-controlled body had rubber-stamped even obviously unqualified nominees like Education Secretary Betsy DeVos.

Is Puzder just that much worse than Trump’s other picks? Or is the climate in Washington changing in just the days since the vote to confirm DeVos?

The Trump administration has careered from crisis to crisis, and on Monday night National Security Adviser Mike Flynn resigned over his conversations with the Russian ambassador. Trump’s fellow Republicans are getting antsy. After trying to shield the new president from oversight, senators now seem to be leaning toward a more aggressive inquiry into the administration’s Russian ties.

There were certainly good reasons for the Senate’s refusal to approve Puzder. The head of the company that owns Hardee’s and Carl’s Jr., Puzder had come under criticism for his business record as well as allegations of domestic violence once lodged against him by his former wife. He also acknowledged hiring an illegal immigrant as a housekeeper, the sort of infraction that has sunk cabinet nominations in the past.

In the minds of Republican senators, the argument for approving bad Trump nominees and looking the other way at his scandals boils down to party loyalty. Senator Rand Paul said as much, in an astonishingly candid comment Tuesday: “I just don’t think it’s useful to be doing investigation after investigation, particularly of your own party. . . . We’ll never even get started with doing the things we need to do.’’ Plus, given Trump’s thin skin, there’s no guarantee that he won’t retaliate against his fellow Republicans in some fashion if they exercise their oversight responsibilities.

But the consequences of letting Trump rampage through Washington appear graver every day. His erratic foreign policy pronouncements on China, the Middle East, and Mexico have thrown international relations into turmoil. Conflicts of interest have crept into official White House communications. Congressmen have the power to mitigate the damage Trump is doing, but only if they use it. Hopefully, having drawn the line on Puzder will embolden them to do so more often.