Two results from the US presidential election seem hard to reconcile. Donald Trump won the presidency after gaining what seems likely to be 306 of the 538 electoral college votes available. Hillary Clinton looks set to win the popular vote by a fraction of a percentage point.



That difference is because of the way that votes are distributed in the electoral college system. But another potential explanation has been offered: maybe third-party candidates cost Clinton dear.

Nationally, third-party candidates did relatively well in this election. With most of the ballots now counted, Libertarian candidate Gary Johnson gained over 3% of the popular vote, and the Green party’s Jill Stein got 1%. Altogether, candidates who did not represent either of the two main parties got around 4.9% of the popular vote (in 2012, third-party candidates only managed 1.7%, and in 2008, 1.4%).

It’s easy to see why people point the finger at third-party votes. In Michigan, where the election was so close that the Associated Press still hasn’t called the result, Trump is ahead by about 12,000 votes. That’s significantly less than the 242,867 votes that went to third-party candidates in Michigan. It’s a similar story elsewhere: third-party candidates won more total votes than the Trump’s margin of victory in Wisconsin, Arizona, North Carolina and Florida. Without those states, Trump would not have won the presidency.

But there are a couple of snags to the “third-party votes did it” argument. Firstly, it assumes that a lot of voters’ second choice was Clinton. There’s little evidence that was true. Most polls – which, it turns out were deeply flawed – simply asked: “Who would you vote for if the election were held today?” Rarely was there a follow-up question of: “And who would you vote for if you didn’t vote for that candidate?”

There are three other possibilities besides choosing Clinton as a second choice candidate:

1. Those voters might have chosen a different third-party candidate. For example, Johnson voters might have switched to Stein, or vice versa. If so, that would have had no effect on Trump’s chances of winning.

2. Those voters might have chosen to stay at home rather than vote for someone who wasn’t their first choice. If so, they again wouldn’t have changed Trump’s victory over Clinton – except to make it even larger as a share of all votes cast.

3. Those voters might have chosen Trump as their second-choice candidate. If so, they not only would have secured Trump as the winner of the national popular vote, they could have also bumped up his electoral college votes by claiming Democratic states like Virginia, Minnesota, Colorado and New Hampshire, where Clinton won by a smaller number of votes than those cast for third-party candidates.

In reality, it’s some combination of all of the above. Some third-party voters could have chosen to stay at home, some could have voted for Clinton, and some for Trump. (People don’t act in perfect herds. If pollsters had better understood that, perhaps they wouldn’t have got this election so badly wrong.)

Except that third-party voters didn’t do any of those things. They put their crosses against the name of a candidate they almost certainly knew would not become their next president. Which suggests a strength of feeling that renders all hypothetical “what ifs” a little redundant.