On Sunday, President Barack Obama told NBC’s Chuck Todd that the politics of immigration reform “did shift” as a result of the influx of unaccompanied undocumented children at the nation’s southern border.

New data shows he’s right about that.

A new poll from NBC News and the Wall Street Journal shows that 53 percent of Americans support granting undocumented immigrants a pathway to citizenship, while 45 percent oppose it.

Compare that to last April, when 64 percent supported it and 35 percent opposed it.

“That’s a big shift in American attitudes,” says Republican pollster Bill McInturff, who conducted the survey with Democratic pollster Peter Hart and his colleagues at Hart Research. “And it’s a reminder of how much the Central American children story has ruptured and re-raised this topic in a difficult way.”

The intensity of opposition to a citizenship plan has jumped too, McInturff notes. Last year, 21 percent said they strongly opposed the idea, while 29 said they strongly supported it; now, 27 percent say they’re strongly against it and 21 percent strongly support it.

(It’s worth noting that this shift came when respondents were asked about “a proposal to create a pathway to citizenship that would allow foreigners who have jobs but are staying illegally in the United States the opportunity to eventually become legal American citizens.” The gap between April 2013 and now is narrower when poll-takers heard more details about the tenets of a bipartisan immigration reform plan, including the requirements that undocumented immigrants pay a fine, pay back taxes and pass a background check.)

So: who has changed their mind about immigration reform?

One of the most precipitous declines has come from Republicans. In April 2013, before the Senate passed a comprehensive deal that was ultimately rejected by the GOP-led House, almost half – 47 percent – of Republicans said they favored a path to citizenship. That number is down 15 points to just 32 percent. (However, if offered more details about the requirements for citizenship, a majority – 64 percent – of self-identified Republicans still say they support it.)

African-Americans have also seen a noteworthy slide in support for the citizenship proposal. Now, 59 percent of black respondents back it, versus 75 percent who supported it last spring.

Backing for a pathway to citizenship has also fallen by double digits among seniors (down 11 percent), women (down 14), young people (down 10) and whites (10 points). Support from respondents aged 50-64 dropped 16 points, from 63 percent last year to 47 percent now.

One place where the shift doesn’t seem to be happening is among Hispanics.

Despite widespread disappointment among immigration activists about the failure to achieve reform – either through legislation or executive action – Hispanic support for the plan remains high at 77 percent.

Perhaps most striking in the run-up to the November elections is how polarizing immigration reform has become in states with key midterm races. Respondents in states with a closely contested Senate race are evenly split (48 percent supporting to 49 percent opposing) on the issue of a path to citizenship.

That explains why ads about “amnesty” are popping up even in states far removed from the nation’s southern border, McInturff notes.

“Now we have … campaigns in the northeast, in other parts of the country, running immigration spots,” he said. “And the difference is how the central American kids totally reopened the dialogue about whether our borders are secure.”