

Actually, it's not so simple. While it's inconceivable that anyone other than the major-party candidates could win the popular vote, it's possible that nobody wins a majority in the electoral college. If there's no electoral majority, the 12th Amendment specifies that the House of Representatives, voting by state, will choose the president among the top three. It's only happened once - in 1824, when John Quincy Adams won despite Andrew Jackson's having gained popular and electoral pluralities - but it's not too much to expect in this bizarre political year.
One could imagine a scenario where former New Mexico governor Gary Johnson, the Libertarian Party nominee, wins his home state and possibly others. He's apparently drawing slightly more support from Clinton than from Trump - which would prevent Hillary from simply sweeping pluralities in all the swing states - and has been polling in double-digits in a three-way race. Or maybe Mitt Romney gets into the mix, or outspoken Sen. Ben Sasse, R-Neb., or someone else conjured by Weekly Standard editor Bill Kristol (a leader of the #NeverTrump movement). If such candidates campaign strategically, they could win electoral votes. In 1968, the segregationist George Wallace won five states and 46 electors.
Moreover, faithless electors, who don't vote for the candidate to whom they're pledged, have appeared in seven of the 14 elections since Alaska and Hawaii began voting in 1960. (John Edwards got one in 2004!) Given the major candidates' (un)favorability ratings, the "faithlessness" probability is high - and it won't take many votes in a close race to deny either Trump or Hillary a majority. ?USA TODAY