The next two days look to be the most tumultuous and telling of the wild, never-ending 2020 election.

Driving the news: Twin runoffs in Georgia today determine control of the U.S. Senate. And perhaps half or more of the Republicans in Congress will cast an unprecedented number of votes to invalidate President-elect Biden’s clear win, as the House and Senate meet to certify the Electoral College votes.

Why it matters: It's insane and revealing that those joining the protest — more than 100 House members (and perhaps 140+), plus 13 senators — could amount to more than half of Capitol Hill's Republicans.

• This shows the political strength could maintain in exile, tormenting Senate Republican Leader Mitch McConnell and other establishment Republicans.

Reality check: The Republican lawmakers won't change the outcome, but they'll drag out what's usually a low-drama process.

• As Speaker Pelosi put it Sunday in a memo to House Democrats: "At the end of the day, which could be the middle of the night, Joe Biden and Kamala Harris will be officially declared the next President and Vice President of the United States."

The 2020 election's final fight could be in the streets: A law enforcement source tells me tens of thousands of people — mostly pro-Trump, but perhaps some from the left — are expected to converge on Washington tomorrow as Congress meets.

• Trump has tweeted repeated promotions for the "Stop the Steal" protests.
• D.C. Mayor Muriel Bowser asked residents to stay away from downtown — and said the District has mobilized the National Guard, and will have every city police officer on duty to handle protests, the WashPost reports.

At a rally in Georgia last night for the GOP Senate candidates, Trump continued his baseless claim that he won the state: "Big difference between losing and winning and having it stolen ... We win every state, and they're gonna have this guy be president?"

• Trump tried to publicly pressure Vice President Pence, who'll preside over tomorrow's proceedings: "I hope Mike Pence comes through for us ... He's a great guy. 'Course, if he doesn't come through, I won't like him quite as much."
• He also denounced "y0ur incompetent governor" and "your crazy secretary of state" — both Republicans — as he plugged Georgia Sens. Kelly Loeffler and David Perdue.