Let me take you on an emotional journey that played out over the course of about 15 minutes on political Twitter this morning. First, shock and scandal:

Next, confusion and suspense:

Finally, resolution and catharsis:

That’s not really resolution, though, is it? Grassley acknowledging that he’d fill in if Pence doesn’t show is worlds apart from claiming that “we don’t expect him to be there.” Why did he not expect Pence to attend? Is the VP looking for an escape hatch behind the scenes, with Grassley getting ahead of the announcement? Or was Grassley simply speculating that Pence will wimp out in the end even though he has no indication at the moment to think so?

The problem with believing that Pence will bail out is that bailing out doesn’t solve his problem. Trump and his supporters are counting on the veep to disrupt the certification of Biden’s win somehow. If he fails to do that, it doesn’t matter how he fails: Presiding over the certification and rubber-stamping it would be the ultimate betrayal, but meekly stepping aside to let Grassley do it would produce the same result. And it would leave Pence looking like an abject coward.

There’s no way out of the Faustian bargain he’s made. If he wants to join the coup effort, he’ll either do it forthrightly tomorrow or be savaged by MAGA regardless of whether he shows or not.

The MAGA-in-chief is watching closely:

Pence now faces an agonizing dilemma. Should he wipe his ass with the Constitution or should he, you know, not do that?

Two people briefed on the discussions said Mr. Trump had directly pressed Mr. Pence to find an alternative to certifying Mr. Biden’s win, such as preventing him from having 270 electoral votes and letting the election be thrown to the House to decide…

On Monday, after Mr. Pence returned from Georgia, the vice president and Mr. Trump were expected to hear a last-minute pitch at the White House from John Eastman, another Trump lawyer. Mr. Pence also met with Senate parliamentarians for hours on Sunday to prepare himself and the president for what he would say while on the Senate floor.

The fact that Mr. Pence’s role is almost entirely scripted by those parliamentarians is not expected to ease a rare moment of tension between himself and the president, who has come to believe Mr. Pence’s role will be akin to that of chief justice, an arbiter who plays a role in the outcome. In reality, it will be more akin to the presenter opening the Academy Award envelope and reading the name of the movie that won Best Picture, with no say in determining the winner…

One person close to Mr. Pence described Wednesday’s duties as gut-wrenching, saying that he would need to balance the president’s misguided beliefs about government with his own years of preaching deference to the Constitution.

A fun moment in the aftermath of the session will be Ted Cruz and Josh Hawley being asked whether they think Pence did the right thing by accepting Biden’s victory. Each of them has gone way out on a limb politically, attempting to disrupt certification to prove their supreme devotion to the cause of letting Trump cling to power. Tomorrow they’re going to step off the floor, having just passed the ultimate loyalty test, and be confronted with a new loyalty test: Do you renounce Mike Pence, and all of his works and empty promises? What will they say?

Chad Pergram of Fox notes that Pence is likely to be absent for part of the session due to how long it could be:

If objections are made to a particular state’s electoral results, the House and Senate then debate the matter for two hours before voting on whether to accept them. If, say, six different states face objections, that means 12 hours of debate plus time for the floor votes. The session could easily run past midnight (although that depends on whether Hawley, Cruz, and the rest will in fact object to multiple states’ results or just those in Pennsylvania and Georgia, for example). Pence may duck out for awhile — but that’s okay. What everyone’s watching for is whether he, not Grassley, presides over the final certification of the vote declaring Biden the winner, whenever that happens. If he leaves the floor for eight hours and then returns at midnight to do that, fine.

Maybe that’s how Grassley got his signals crossed about Pence’s intentions, in fact. Pence’s office might have told him that the VP will be there to preside when the session opens and will return to wrap it up, but will let Grassley do the honors during the lengthy objection-and-floor-debate stage.

Exit question: How relentless will Trump be in attacking Pence if/when Pence gavels down Biden’s victory? A few angry tweets in the hours following or “the full Sessions” with sporadic grumbling from now until 2024?

Update: Not even waiting for tomorrow!