An obscure 1887 law called the Electoral Count Act, and several subsequent updates, spell out the process, setting Jan. 6 after a presidential election as the official certification date and outlining vague, complicated procedures.

On that day, the House and Senate meet in a joint session at 1 p.m. — just three days after a newly constituted Congress is sworn in. One of their first orders of business is to pass judgment on the Electoral College vote.

That same federal law also gives a tiny number of lawmakers enormous power to challenge the results.

If a single House member and a single senator join forces, they can object to entire slates of presidential electors. They must do so in writing and provide an explanation, though there are no guidelines on how detailed it must be.

If they do, the House and Senate must retreat to their chambers and debate the outcome for up to two hours before voting on the matter. Each state’s electors are certified separately, meaning lawmakers bent on challenging the results have multiple chances to force lengthy delays.