Trump has had an ongoing war of words with former Mexican president Vicente Fox over who will pay for a new 1,000 mile long border wall. Now the current president of Mexico is weighing in and comparing Trump to Hitler and Mussolini. From the AP:

Asked about Trump, Pena Nieto complained to the Excelsior newspaper about “these strident expressions that seek to propose very simple solutions” and said that sort of language has led to “very fateful scenes in the history of humanity.”

“That’s the way Mussolini arrived and the way Hitler arrived,” Pena Nieto said. Pena Nieto until now had avoided direct comments on Trump, who has pledged to build a wall along the two countries’ borders.

Nieto went on to add that there was, “no scenario” in which his country would pay for a border wall.

There are two strains to the politics of this in the near term. On one hand, having another critic, even a sitting president, attack Trump and claim Mexico won’t build his wall will surely make it that much more exciting when he trots out his trusty, “and Mexico will pay for it,” line at the next big rally. Trump’s supporters like that he is confrontational so this is unlikely to hurt him in the short term. In fact, Trump can probably spin this into an over-reaction to his populist proposal.

On the other hand, part of Trump’s appeal is that he’s a great deal maker who promises to make better deals on behalf of the country. Having the current president of Mexico veto your proposal before you are even elected seems like a sign that Trump’s deal-making strategy on the border wall needs some fine tuning. Can he spin this rejection by the person he would need to broker his #1 priority with as a win for his business acumen? At what point does that begin to sound dubious to his supporters?

In the longer term, the anti-Trump ads created by Hillary Clinton really write themselves. Whether that will have an impact on Trump’s standing with the electorate probably depends on how Americans are feeling about immigration come November. A new survey by A.T. Kearney, results of which were published by Bloomberg, finds that Americans appear to be very unhappy about immigration at this moment. In fact, they believe it puts the United States’ future prospects in jeopardy:

Sixty-one percent of Americans agree that “continued immigration into the country jeopardizes the United States,” according to a new poll commissioned by management consulting firm A.T. Kearney that revealed pessimism across a wide range of issues…

A belief that immigration jeopardizes the U.S. was common across age groups, although highest among baby boomers (65 percent) and lowest among millennials (55 percent). By education, it was highest among those with just a high school education or some college (65 percent), and by region it was highest in the South, including Texas (66 percent).

Other polls asking similar (but not identical) questions have given very different results. A Pew survey last year found a majority of respondents saying they felt immigration strengthened the U.S. If the populist feeling toward immigration really is as strong as A.T. Kearney’s survey suggests, it seems there are a lot of Americans ready for a more aggressive approach to dealing with the border and the President of Mexico.