With the latest phase of the House impeachment inquiry having concluded on Thursday, the country appears headed for a full impeachment vote in the House of Representatives followed by immediate proceedings in the Senate. Be prepared, though, for a trial not just of President Donald Trump, but of Joe and Hunter Biden as well.

Every indication after two weeks of hearings before the House Intelligence Committee is that Trump is likely to be impeached for his actions in the Ukraine affair. The main charge—as evidenced by public testimony, emails, texts, and the president’s own call record—is that Trump sought to get the Ukrainian President Volodymyr Zelensky to announce an investigation into one of Trump’s top political rivals, Joe Biden, and his son Hunter, as an apparent condition of an Oval Office meeting with Trump and the release of hundreds of millions of dollars in U.S. military aid. After moderate Republican Rep. Will Hurd strongly indicated on Thursday that he would not be supporting impeachment, it looks like it will come down to something like a party-line vote in the House. With Democrats controlling that body, an impeachment of Trump seems all but assured. This would move the action to the Senate, perhaps as early as January, where the president will be on trial over whether he should be removed from office and disqualified from running again.

There’s every reason to believe Trump will try to mount an extended attack on Biden as part of his defense in a Senate trial.

House Intelligence Committee Chairman Adam Schiff focused his committee’s hearings on the question of Trump’s actions, and he blocked attempts by Republicans to call witnesses to make the hearing about the actions of the Bidens. Hunter served on the board of Burisma, a Ukrainian natural gas company, and Trump has claimed without evidence that Joe Biden had interfered in Ukraine while vice president to stop an investigation of Hunter. Schiff also did not call witnesses that might even remotely advance Trump’s discredited theory that it was Ukraine, acting with the company CrowdStrike, rather than Russia, that interfered with the 2016 presidential elections (though it’s also hard to imagine who those witnesses might be). In addition to asking for a probe of the Bidens, Trump requested an inquiry of CrowdStrike during his July 25 call with Zelensky and re-upped that conspiracy theory in an interview with Fox and Friends on Friday. Republicans like Rep. Jim Jordan and ranking member Devin Nunes have brought up the notion that Ukraine interfered in the 2016 election in questioning Democratic witnesses in the House, but that’s not the same as being able to call witnesses to focus on the Biden angle and CrowdStrike.

But when action shifts to the Senate, Schiff will no longer be in charge. He, or others from the Democratic side in the House, will act like prosecutors in bringing the case, but Republicans control the Senate. It will be up to Senate Majority Leader Mitch McConnell and Chief Justice John Roberts to determine whether a Biden-centered defense will go forward.

There’s every reason to believe Trump will try to mount an extended attack on Biden as part of his defense in a Senate trial. Someone familiar with the Trump camp strategy told Politico that “they want some kind of factual affirmative defense on the merits,” and Trump himself on Friday said, “I want a trial.” It appears the affirmative defense would be that Trump pressured Zelensky because he was worried about corruption coming from the Bidens, and not because he was seeking dirt on a political rival. (This is almost laughable.)

According to the New York Times, Sen. Lindsey Graham, who chairs the Senate Judiciary Committee, is already laying the groundwork for this defense. Graham sent a letter to Secretary of State Mike Pompeo seeking evidence to sully the Bidens:

In the letter, Mr. Graham asked for documents and communications with former Vice President Joseph R. Biden Jr., his son Hunter Biden, officials from the Obama administration and former President Petro O. Poroshenko of Ukraine. The list suggests that Mr. Graham envisions a defense of Mr. Trump that focuses on shifting attention away from Mr. Trump’s conduct and onto the issue of whether Hunter Biden’s work on the board of a Ukrainian energy company while his father was vice president was appropriate.

A trial of Biden or CrowdStrike in the Senate could be a Trump victory, or it could be a morass for Senate Republicans. Remember that the whole point of pressuring Ukraine was not to get the government there to actually do an investigation but only to announce an investigation. The goal was not to get at the truth but to open up a line of attack on the man Trump saw as his most dangerous rival. Trump was banking on the premise that it could be enough to sully someone’s reputation repeatedly through public attacks rather than to have to produce actual evidence to harden public opinion. Days of Senate hearings in which Trump lawyers lay out a case against Joe Biden or CrowdStrike will presumably get wall-to-wall coverage from major news outlets, further amplifying Trump’s lies against Biden and efforts to blame Ukraine and rehabilitate Russia for the 2016 election interference campaign.

Now some moderate senators like Maine’s Susan Collins may balk at such a defense, but they really have very little control here. Just like a criminal defendant, Trump gets wide latitude to launch his defense. It seems unlikely that the chief justice would shut down an attempt by Trump to present evidence supposedly going to his state of mind in pressuring Ukraine. Trump’s state of mind is crucial in determining whether he abused his power and acted corruptly.

It’s already clear that Trump will try to use the Senate trial to his political advantage. The strategy is a gamble, but it could pay off. Conviction takes a two-thirds vote, which would mean near two dozen Republican senators joining the Democrats to convict, an outcome that would not be possible if the vote were held today.* In the likely event that Trump is acquitted after sullying Biden, the president will take a victory lap and perhaps turn to new ways to curry foreign interference in the upcoming 2020 elections. It will still ultimately be up to American voters to determine if they will side with those presenting evidence of the president’s abuse or with those peddling Trump’s false conspiracy theories.

Correction, Nov. 24, 2019: This article originally stated that conviction in the Senate would require near three dozen Republican senators joining the Democrats. It would require near two dozen.