Senate Republicans may be back on track with their plan to end President Trump’s impeachment trial pretty swiftly now — without calling witnesses and potentially as soon as Friday. That seemed a little less likely on Monday, when news of former National Security Adviser John Bolton’s recollections of conversations with Trump about Ukraine seemed to open the door to a more drawn-out trial that included Bolton and other witnesses.

That door is still open, but Senate Republicans haven’t exactly stampeded through it. In a private meeting on Tuesday, a group of GOP senators in competitive races — Joni Ernst of Iowa, Cory Gardner of Colorado, Martha McSally of Arizona and Thom Tillis of North Carolina — told their colleagues that they were opposed to a drawn-out trial, according to CNN. The only Republicans who seem almost certain to support witnesses in a vote are Susan Collins of Maine and Mitt Romney of Utah.

That’s not enough. It’s not clear if Chief Justice John Roberts would break a 50-50 tie or if he would abstain from a vote. But a 50-50 result would be considered unsuccessful, so Democrats would need 51 votes without Roberts. And there still aren’t 51 votes for witnesses. At least one and likely two Republicans would need to join Collins, Romney and the Senate’s 47 Democrats to include witnesses in the trial.

But there’s still a ton of uncertainty about how all this will play out. On Tuesday afternoon, McConnell privately told GOP senators that there were not yet 51 votes against having witnesses either. In other words, there’s not a clear 51 votes against witnesses or for witnesses. It’s possible, if not likely, that a sizable bloc of Republicans want witnesses (and just haven’t said so publicly) and that eventually McConnell will concede to that group and propose some kind of plan to meet that demand over the objections of Trump and his legal team.

Wednesday starts a 16-hour process that will extend into Thursday in which senators can submit questions to the House Democratic impeachment managers and the president’s legal team. Roberts will read the questions, including the name of the senator who submitted them. These sessions are likely to be more dynamic than the other parts of the trial, which were largely Democrats and then Trump’s lawyers repeating arguments they have been making for months about Trump and his administration’s policies toward Ukraine.

I would also expect Wednesday to include more behind-the-scenes wrangling, with McConnell continuing to implore senators not to push for witnesses and Trump’s allies going on Fox News and Twitter to attack Bolton and suggest he is being disloyal to Trump and the Republican Party. And watch out for more unexpected developments as well, such as when news emerged on Tuesday that one-time White House Chief of Staff John Kelly had said a day earlier that, “If John Bolton says that in the book, I believe John Bolton.” Like Bolton, Kelly clashed with Trump while serving as one of the president’s top aides.

Friday is still the big day in this process. Republicans will either vote to allow witnesses and potentially a longer trial — or move to acquit Trump and end impeachment.

CLARIFICATION (Jan. 29, 2020, 2:27 p.m.): This article has been updated to more precisely describe CNN’s reporting on a closed-door meeting attended by Republican senators on Tuesday.

This is part of a series of regular, short updates on the impeachment process.

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