President Trump speaks on the phone with Australian Prime Minister Malcolm Turnbull in the Oval Office of the White House on Jan. 28. (Alex Brandon/AP)

At the 2015 Iowa State Fair, in the early days of the Donald Trump phenomenon that culminated last month in the Oval Office, I spoke with a Republican woman from New Jersey named Peg Wills. Wills was intrigued by Trump but had a hesitation. “Trump going overseas to say what he thinks,” she said, “might not be the wisest choice.”

Wills’s fears were likely fulfilled by The Post’s report on Trump’s conversation with Australian Prime Minister Malcolm Turnbull. Trump, making the last of a series of calls late in the day, angrily told Turnbull that the conversation was “the worst call by far,” after being pressed on an American commitment to accept 1,250 refugees from our close ally. “Trump’s behavior suggests that he is capable of subjecting world leaders, including close allies, to a version of the vitriol he frequently employs against political adversaries and news organizations in speeches and on Twitter,” our Greg Miller and Philip Rucker wrote.

The question is one of temperament. Americans have a loosely defined sense of what is and isn’t presidential and what sort of temperament it takes to hit that standard. When pollsters would ask the country if they thought Trump hit that mark, a majority of Americans consistently said that he didn’t. In every poll conducted before the election a clear majority said that Trump lacked the proper temperament for the job.

If 60-some percent of the country thinks Trump lacks the right temperament and he got only 40-something percent of the vote, one might think that perhaps his support derived entirely from those who didn’t doubt that he had the temperament. But that’s not the case. In a Fox News poll conducted shortly before the election, 15 percent of Trump backers thought he lacked the proper temperament. That was three times the percentage of Hillary Clinton backers who thought she lacked the right temperament.

Exit polls suggest that Fox’s numbers may have been low. In exit polling, more than a quarter of Trump supporters thought he lacked the proper temperament for the job — but they voted for him anyway.

This was a central part of Clinton’s campaign strategy: Reinforce that Trump was simply unacceptable for the job. She clearly didn’t need to do much to reinforce that point, but, regardless, it doesn’t seem to have worked.

Why not? How could someone think that a candidate was unfit for the office but still vote for him? The answer lies in those same exit polls.

When asked to compare the two major-party candidates, you can see that a substantial chunk of the electorate — 14 percent of voters — thought that neither candidate had the right temperament.

Among those voters, two-thirds voted for Donald Trump.

This is where the Clinton strategy failed. She thought that she could win the White House by reinforcing people’s concerns about Trump. Trump and his allies, though, were effective at dragging down perceptions of Clinton, too, giving many voters the sense that they were having to pick between two unacceptable choices. Those voters picked Trump.

There are certainly some Trump voters who support him specifically because they like his brash willingness to dismantle decorum. Many others, though, backed Trump because they didn’t see Clinton as being any better.

It’s safe to assume that had Clinton been in the White House for that call, the conversation would have been different to the point of non-newsworthiness. But the fact that Trump’s call went south surprises no one, simply because America — from Peg Wills in August 2015 to voters on Election Day — always understood that this is who Trump was.