The Electoral College will meet on Monday to vote to determine who won the presidential election. The expected winner is President-elect Joe Biden, but some of President Trump’s allies in Congress have already hinted they won’t accept this result — even after the Electoral College makes it official.

Last month, Republican Rep. Mo Brooks of Alabama announced his intention to challenge the Electoral College’s votes if Biden is declared the winner. Several House Republicans have since joined Brooks’s effort, according to Axios, though he’d need at least one senator to sign on to his written objection in order for it to move forward in Congress. It is not clear whether any senators will object.