Talks with Mexican officials are not making “nearly enough” progress in curbing the Central American migration into the United States, said a tweet from President Donald Trump.

Negotiations with Mexico will continue on Thursday, Trump added.

Mexico’s diplomatic position likely includes continued opposition to the U.S. demand that Mexico sign a “safe third country” agreement. The agreement would allow the U.S. to reject and then return migrants who travel through Mexico to reach the U.S. border.

But Mexico’s chief negotiator admitted the political crisis during a press conference after the talks, and after officials had announced that 140,000 migrants crossed from Mexico into the United States during May. “Today the [May] numbers report was published, and indeed the flows are growing too much, so they can’t be maintained as they are,” Foreign Minister Marcelo Ebrard said. “Both sides recognize that the current situation cannot be maintained as it is,” he added.

The failure of the talks is a threat to Mexico’s economy. On Wednesday, U.S. financial markets downgraded Mexico’s economic forecasts.

But Democrat legislators and the establishment Republican senators are aiding Mexico’s hard-line stand, even as 350,000 migrants transited Mexico in March, April, and May.

House Majority Leader Nancy Pelosi (D-CA) effectively endorsed the Mexican government’s policies, said José Díaz-Briseño, correspondent for the Mexican newspaper Reforma. “Perhaps most vocal & politically relevant endorsement of Mexico of the past days in the US,” Díaz-Briseño tweeted after Pelosi questioned Trump’s legal authority to impose tariffs on what she said are “our allies.”

“I think that this is dangerous territory. This is not a way to treat a friend,” she said on June 5.

The Democrats’ Senate leader, Sen. Chuck Schumer (D-NY) also undermined the U.S. president’s diplomatic clout, saying:

I don’t believe President Trump will follow through on this threat to impose tariffs on Mexico … the president has a tendency for bluster … most Republican senators oppose the President’s idea of slapping tariffs on Mexico … I continue to believe he will back off.

Democrats want to let migrants apply for asylum in their home countries and increase the number of immigration judges to reduce the backlog, Schumer said.

But those Democrat policies would legalize — and perhaps not even reduce — the Central American migration into Americans’ blue-collar worksites, neighborhoods, and schools.

The Democrats’ hard-line opposition to Trump’s policies helps explain why Trump is negotiating with Mexico instead of Congress, said a tweet from Josh Holmes, a former chief of staff and campaign manager for Senate Majority Leader Mitch McConnell (R-KY). He tweeted:

While mainstream news pounces on the tariff divide in the gop, the reality is that this Mexico tariff decision signals that the Administration believes it’s easier to deal with Mexico than Democrats on our humanitarian crisis at the border. Much bigger story.

Meanwhile, House GOP Leader Rep. Kevin McCarthy (R-CA) criticized the group of GOP senators who said tariffs should not be used to help Americans protect their workplaces from cheap-labor migration.

Those GOP senators — and their donors — however, have silently accepted Trump’s use of other tariffs to protect American companies and investors from China’s predatory economic policies.

Mexican negotiators said the Wednesday talks with Vice President Mike Pence and Secretary of State Mike Pompeo focused on migration, not on tariffs.

“We are optimistic,” said Ebrard.

In 2018, Ebrard quietly agreed to accept Trump’s “Remain in Mexico” plan, which allows U.S. officials to return some migrants to Mexico, pending their subsequent immigration hearing. But that plan has kept around 6,000 migrants in Mexico, even as almost 350,000 migrants have crossed the border during the last three months.