Wednesday’s joint session of Congress to count Electoral College votes from the presidential election is a largely ceremonial event that in the past has taken as little as 23 minutes.

But with objections threatened by House and Senate Republicans, it has the potential to play out for more than 24 hours.

At least 13 GOP senators and more than 100 House members have said they will object to state electors, in an effort to show support for President Trump’s unsubstantiated claims of widespread voter fraud.

President-elect Joe Biden received 306 electoral votes, while Trump received 232 electoral votes. At least 270 electoral votes are needed to be elected president.

How did we get the Electoral College, and why do we still have it?

“The Constitution is clear; the results of the election are clear; the conclusion of courts of the land is clear,” House Majority Leader Steny Hoyer, D-Md., said on Tuesday. “I expect without a doubt that the report of the Electoral College and the 306 electoral votes that Mr. Biden got will be confirmed at the end of this process.”

Here’s what you need to know.