(Evan Vucci/AP)

Opinion writer

President Trump has spent the last half day frantically retweeting his propagandists, who are pushing the absurd deception that Trump’s new deal with Mexico is a massive and historic victory. In reality, the agreement — which averts Trump’s threatened tariffs — consisted mostly of things Mexico already agreed to months ago.

Trump is in a rage over this — he repeatedly fumed at the New York Times for reporting it — and now he’s amplifying the notion that he won enormous concessions from Mexico by claiming that Mexico has secretly agreed to another major provision that will be revealed at some unspecified future time.

This has come packaged with a threat: Trump just tweeted that if Mexico does not soon take formal steps to ratify that secret provision, “Tariffs will be reinstated!”

But this threat gives Democrats a big opening to grab control of this debate — both on the immigration and trade fronts, because this story intertwines the two, and more broadly to better engage with the colossal failures of Trump’s nationalism.

The two main provisions of the deal that Trump reached with Mexico are an expansion of a program in which asylum seekers trying to enter the United States wait in Mexico; and increased deployment of Mexico’s national guard to disrupt smuggling networks and try to stop migrants from Central America from reaching the southern border.

Those could have some impact on flows. But critics are understandably skeptical that they will put much of a dent in the larger asylum problem, which is driven by a combination of root causes in home countries and resource shortages to process claims and handle what has become a new kind of humanitarian challenge.

Regardless, the Times reports that Mexico already agreed months ago to both major provisions. While it’s possible that the threat of tariffs accelerated their implementation, Trump’s handling of this affair raises serious questions about whether he rattled diplomatic relations and supply-chain arrangements for no good reason, and by extension, about our reliability as a trading partner.

As for the secret provision Mexico supposedly agreed to, the White House has mysteriously declined to clarify. It could be negotiations over a “safe third country” treaty, which would mean enormous numbers of migrants waiting in Mexico, with uncertain humanitarian outcomes — but officials on both sides say no such agreement was reached.

Either way, now the threat of tariffs is back, which should only magnify the concerns that they sparked in the first place.

Beto O’Rourke’s good answer

Asked on ABC’s “This Week” to comment on Trump’s Mexico mess, former Texas congressman and 2020 Democratic presidential candidate Beto O’Rourke offered an answer that’s worth watching in full:

Note that O’Rourke used this situation as a window into a much broader indictment of Trump’s nationalist agenda. He stressed that the threat of tariffs against Mexico is only serving to “jeopardize” our “most important trading relationship”; that this places at risk markets that our farmers have cultivated; and that they are already taking a beating from Trump’s trade wars with China.

Importantly, O’Rourke made the case that precisely the opposite approach — strengthened, reality-based international integration — is the answer both on trade and on immigration. O’Rourke called for trade arrangements in farmers’ and workers’ interests and for increased investments in Central America “to ensure that no family has to make that 2,000-mile journey.”

A better Democratic response

This hints at the outlines of a better Democratic response to Trumpian nationalism in 2020. Trump’s trade war with China is dragging on and harming his own constituencies. This, combined with the chaos attending the threats against Mexico, gives Democrats a good argument: that in practice, Trump’s nationalism is reckless, often driven by impulse and rage, and out of sync with the complex realities of international diplomacy and the global economy.

As Neil Irwin argues, Democrats can pledge to move away from two-country tariff wars and instead toward mobilizing an international response with allies against China’s trade abuses. Similarly, Democrats can argue for renegotiated trade deals that raise wage, labor and environmental standards, with the goal of helping U.S. workers via a sensible internationalism in contrast to Trump’s erratic nationalism.

Joe Biden has already started road-testing such an argument. And O’Rourke’s new comments move in this direction as well.

Indeed, the way O’Rourke wove in his arguments on immigration also underscores the point. Democrats can argue for improved regional cooperation on the asylum crisis, including investments in Central America and policies to encourage in-country application for asylum to reduce the impetus to such migrations. They can combine this with a refusal to back off our international humanitarian commitments, as O’Rourke gave voice to, while reminding everyone of Trump’s horrific family separations.

This again would contrast with the recklessness and impulsiveness of Trump’s nationalism, which has led Trump to cut off aid to Northern Triangle countries and try to dissuade migrations with ever-mounting cruelties and “toughness,” an approach that’s largely failing.

One can see such a Democratic argument appealing to both working people (who might have once thrilled to Trump’s anti-China bluster, but are taking hits from Trump’s trade wars and are uncomfortable with Trump’s more grisly immigration horrors) and to college-educated whites who are already alienated by the hideous realities of America First-ism — and are likely comfortable with internationalist solutions on both issues.

Now that Trump has once again threatened Mexico with more tariffs, Democrats have a new opening to press this case more comprehensively.

Read more:

Hugh Hewitt: Trump’s big win leaves critics sputtering

The Post’s View: How Trump and Congress can really fix our immigration problems

Carla A. Hills: You can’t stop migrants with tariffs

Fareed Zakaria: Trump is destroying three decades of hard work with Mexico

Robert J. Samuelson: There is a sheer nastiness to Trump’s Mexico tariffs