Sen. Marco Rubio (R-Fla.) had this exchange on CBS Thursday morning:

JOHN DICKERSON: Senator, President Trump tweeted yesterday that Attorney General Jeff Sessions should end the special counsel Russia investigation. He’s called it again a rigged witch hunt. Is that obstruction of justice?
RUBIO: Well, I don’t know what the legal definition of that would be with regards to tweets. I don’t think that’s ever been litigated. Here’s the bottom line. I’m not going to spend my time here in the U.S. Senate waking up every morning and responding to some tweet every day. I know that’s what you guys are paid to do, and that’s fine if it’s something directed at public policy, but I’m going to spend my time in the U.S. Senate working on paid family leave. I’m going to spend my time in the U.S. Senate fighting against the efforts of the Chinese to overtake us in the geopolitical stage. I’m going to spend my time fighting for the people of Florida on issues that are important. When something big comes up that needs to be addressed, we’ll address it. My views of the Mueller investigation are clear. I think he should be allowed to finish his work. Let all the truth come out, and that the truth is going to be good for the president and good for America. That remains my view. If the president has a different view, that’s his right. You guys can ask him about it. You can ask the White House about it.

There are two possibilities here: Either Rubio is being disingenuous or he actually means what he says. I suspect it is the former and this is simply one more excuse for not confronting Trump’s illegal and unconstitutional actions or for not defending U.S. democracy. Not my job!

It would be worse if Rubio actually believed his job was simply to pass bills. That’s not what his oath of office says or what the Constitution demands of him. To refresh everyone’s memory, the oath begins: “I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic …” That’s the oath Rubio took, not a vow of silence.

He is there to defend our democracy, whether that threat comes from the president of the United States or the president of Russia. He’s there to protect an independent judiciary and to act as a check against a president who brazenly and openly seeks to derail a legitimate investigation in the president’s possible collaboration with a hostile power to win the presidency. I’m not sure what legislation Rubio is toiling away at 24/7 (it’s not the GI Bill or the Civil Rights Act, to be sure) that leaves him no time to opine, but whatever it is, that legislation pales in comparison to the obligation of oversight, the obligation to speak out in defense of our democracy and the obligation — if he loves passing legislation — to enact a law protecting special counsel Robert S. Mueller III and Deputy Attorney General Rod J. Rosenstein.

Rubio is hardly alone, of course. It’s par for the course. Trump’s assault on democracy, the press and an independent judiciary would not continue if Republicans firmly and explicitly called him out. They have the power to vote on resolutions and on legislation. They have the power to conduct searching, serious oversight rather than put the FBI and the Justice Department on trial in their kangaroo courts. We’ve come a long way from a GOP that fancied itself as a guardian of the Constitution. Now Republicans cannot manage to defend their institution as a co-equal branch of government and check on the president. What better reason to take the majority away from them?