When do the electors’ votes have to be certified by?

Federal law requires that electors meet in their respective states and formally send their vote to Congress on ‘‘the first Monday after the second Wednesday in December’’. This year that date is December 14.

Under US law, Congress will generally consider a state’s result to be ‘‘conclusive’’ if it is finalised six days before the electors meet. This date, known as the ‘‘safe harbour’’ deadline, falls on December 8 this year.

Those votes are officially tallied by Congress three weeks later and the president is sworn in on January 20.