Now that they have the votes to pass a bill revamping the tax code, Senate Republicans are on the verge of accomplishing something that has eluded them all year: fulfilling a major campaign promise. Politically speaking, it's a much-needed victory after they failed to repeal Obamacare this summer.

But oh, the irony. Advancing a tax bill has been hugely overshadowed by literally the last thing Republicans want to talk about: a massive development in the investigation into whether their president’s campaign colluded with Russia. On the same day Senate Republicans were set to pass the first reform of the tax code in three decades, President Trump's former national security adviser pleaded guilty to lying to the FBI about his conversations with the Russian ambassador.

It’s the most significant development yet in special counsel Robert S. Mueller III's investigation into Russia meddling, one that brings the investigation through the inner gates of the White House. It’s very likely Michael Flynn is cooperating with investigators to share what he knows. It also seems this investigation isn’t cooling down, as some in the Trump White House have claimed. It ramped up in a major way Friday.

By now, Republicans in Congress are used to Trump stealing the narrative at inopportune times. Trump has been unhelpful, to say the least, on messaging what Republicans want messaged.

When Republicans were trying to pass an unpopular Obamacare repeal, leaders went out of their way to say what a great job Trump was doing selling it. (“This is a power we haven't seen since Ronald Reagan,” House Speaker Paul D. Ryan [R-Wis.] said at one point of Trump's involvement.) All evidence was to the contrary. Trump went to Michigan around the same time and didn’t publicly mention health care once.

Trump has also demonstrated an uncanny knack for launching a headline-dominating controversy at the exact moment congressional Republicans want to talk about something else.

In June, Trump attacked a cable TV news host in very personal and gender-oriented terms on the same day House Republicans handed him a rare legislative victory on sanctuary cities. (The bill has stalled in the Senate.)

And this week, Trump retweeted three unverified videos that were condemned by many as anti-Muslim on the same day Republicans passed their tax bill out of committee.

Last week, Trump went after Sen. Jeff Flake (R-Ariz.) right when Republican leaders were trying to win him over to their tax bill.

Friday’s dueling news stories, of course, are not directly Trump’s doing. He had no involvement in the special counsel’s decision to charge Flynn, nor in Flynn’s decision to take the plea deal in exchange for cooperating with investigators.

But it’s safe to say Flynn wouldn’t be in this position if Trump hadn’t hired him, and the Russia investigation wouldn’t be ramping up at the exact time congressional Republicans want the focus on their win.