Vice President Joseph R. Biden Jr. performs his last constitutional act by presiding over the joint session of Congress Friday in the House chamber for the official acceptance of the Electoral College results from the states.

The Constitution directs Biden to break the seal on the results from the Electoral College votes held Dec. 19 in the state capitals and then tally the results to determine if a candidate has a majority of the electors. If no candidate has an absolute majority of electors, then up-to-the top three candidates are put up for a new election by the House of Representatives.

For the vote in the House, each state delegation votes among themselves and the winner inside the delegation is awarded the state’s single vote.

Given that the Republicans hold the majority of 36 delegations, the Democrats hold 13 and Maine is a 1-1 tie, if the vote goes to the House, Trump wins in a huge landslide.

The Electoral College is also determined by state, except Nebraska and Maine, which allow congressional districts to vote separately, regardless of the statewide vote. Voters are actually voting for a slate of electors chosen by the presidential candidate’s party to participate in the real election that happened in November.

When Americans voted Nov. 8, Republican Donald J. Trump beat Democrat Hillary R. Clinton 306-to-232, when that vote was translated into the Electoral College. But in keeping with the constitutional plan, electors are free to vote for whomever they please, though some states have laws meant to bind them. After the vote Dec. 19, Trump led Clinton 304-to-227.

It is the 304-to-227 tally that Biden will verify Friday to be approved by the House and the Senate.

There could be a challenge. First, a congressman makes a motion to challenge the tally, followed by a second congressman and one senator to co-sign the challenge.

In 2000, members of the Congressional Black Caucus challenged the results of an election that was marred by irregularities in Florida and one where the recount there was stopped by the Supreme Court just before the Electoral College met. The challenge did not go far because, despite the pleading of the congressmen, nary a senator would join the challenge.

For that spectacle, Vice President Albert A. Gore Jr., was the third man to preside over the final tally of his own defeat — Biden becomes the fourth.

Four vice-presidents have presided over their own victory: John Adams, Thomas Jefferson, Martin Van Buren, and George H.W. Bush.

In 2004, Sen. Barbara Boxer (D.-Calif.) joined House Democrats in their challenge based on results in Ohio, which forced both chambers to separate and to debate the challenge for two hours.