It seems like only about a week ago that the White House issued a statement from President Trump arguing that the Deferred Action for Childhood Arrivals program should be ended because, Trump argued, it encouraged illegal immigration and hurt salaries and job prospects for American citizens.

In fact, it was only about a week ago. On Sept. 5, Trump’s attorney general argued that the program — which allows some of those who immigrated to the country illegally as minors to live and work legally in the country — should be ended. The White House issued a statement from Trump bolstering Jeff Sessions’s arguments. The administration sent out talking points encouraging those in the program to use the six months before it ended to prepare to leave the country.

Even that afternoon, however, Trump seemed conflicted. A bit over a week later, his position on DACA has apparently flipped entirely.

There’s a question embedded in those tweets: Who could possibly want to toss these immigrants out of the country (except for the White House a week ago)? And the answer is: A large percentage of the people who elected Donald Trump.

Shortly before Election Day last year, American National Election Studies pollsters interviewed thousands of Americans about their views on a number of political issues, including the issues at the heart of DACA.

What should happen to those who immigrated illegally as children but who met the criteria of the program, the pollsters asked. Most Americans — including most Republicans and Trump voters — thought they should be allowed to stay and work in the country.

Nearly a fifth of Americans, though, thought that those immigrants should be “sent back where they came from” — a percentage powered by nearly 3-in-10 Republicans holding that position.

What’s most important to note in that graph are the last two numbers. Thirty-two percent of Trump general-election voters thought that DACA recipients should be deported. This isn’t a big surprise: Nearly a fifth of Trump voters in November thought that immigration was the most important issue facing the country, according to exit polls.

But notice that the 32 percent of Trump voters supporting deportation is significantly lower than the 40 percent of Trump primary voters who hold that position. Trump’s primary voters — the core base of support that powered him to the Republican nomination and then the presidency — is more supportive of deporting DACA recipients than anyone else.

We’ve made this argument before, but it bears repeating. A hard line on immigration was central to Trump’s candidacy. His comments about Mexican immigrants “bringing crime” and being “rapists” at his campaign launch spurred a public backlash that, in turn, drew a lot of attention to his campaign and his position on immigration — a position that appealed to a lot of conservative voters but which was anathema to mainstream Republicans. The controversy over immigration allowed him to cement the support of a big chunk of the Republican electorate — a chunk large enough to vault him into the lead in the crowded field and, eventually, push him to the nomination.

Perhaps Trump is making a more nuanced case reflecting the evolution he himself seems to have gone through over the past week: Once people get to know these kids, to think about the issue in a broader context, they’ll change their minds. Given how fervent opposition to illegal immigration is among a number of conservatives, though, it seems unlikely that those views would shift simply because Trump’s position has. Trump once said that he “could stand in the middle of Fifth Avenue and shoot somebody” without losing any support. That argument has proven to be sound repeatedly. But it’s not clear if Trump could stand in the middle of Fifth Avenue and safely grant residency status to an immigrant here illegally.

Trump expressing bafflement that anyone could want to deport DACA recipients is, in a sense, like Trump wondering aloud if there were actually people who would have supported Trump in July 2015. Trump’s presidency was built on the people who Trump now speculates couldn’t possibly exist.

No wonder those people are now angry.