The 12th Amendment, ratified in 1804, directs the electors chosen by the states to meet and vote for president and vice president, conveying the results to the president of the Senate.

That was accomplished Dec. 15, when the electors, in a largely ceremonial rite preordained by Obama's Nov. 4 victory over McCain, gathered in state capitals to cast their votes. As on Thursday, the tally was 365 for Obama, 173 for McCain.

The electoral college is made up of 538 electors, with each state getting its equivalent in the 435-member House and the 100-member Senate. The District of Columbia gets the other three electors.

The session this year was drama-free, unlike in 2001, when then-Vice President Al Gore presided over the session that declared George W. Bush the winner over Gore in a disputed election. Gore disallowed objections from fellow Democrats who asserted that Bush had unfairly won Florida and tried to block Florida's electoral votes from being counted.