President Trump is seen during the "Pledge to America's Workers - One Year Celebration" event in the State Dining Room of the White House on July 25. (Matt McClain/The Washington Post)

The Trump administration has suffered a series of fresh legal and political setbacks in its efforts to tighten U.S. asylum laws, raising doubts about the sustainability of the immigration deal with Mexico that the president announced six weeks ago.

Over the past week, Mexico and Guatemala have pulled back from entering into “safe third country” agreements that would require migrants passing through those countries to apply for asylum there before reaching the United States.

A federal judge in California also blocked a new regulatory provision that aimed to accomplish a similar outcome by denying most migrants entry at the southern border if they had not applied for asylum in the first safe country they reached.

The upshot is that the administration has come up empty in enacting sweeping changes to U.S. asylum policies that President Trump suggested in early June would be a major component in his immigration deal with Mexico to address the mounting humanitarian crisis at the border.

Without those changes, experts said, the administration will have difficulty maintaining and building upon the modest initial progress it has made in reversing a spike of asylum seekers that has overwhelmed the U.S. immigration system and roiled the political debate in the early stages of the 2020 presidential campaign.

“That’s a problem,” said David Inserra, a homeland security analyst at the conservative Heritage Foundation. “If the deterrent is not there, people will show up at the borders. If they are not sent back, that magnet is still on.”

On Capitol Hill, Trump’s allies expressed frustration at the setbacks on asylum and said steps by the Mexican government to add 6,000 national guard forces at its southern border with Guatemala and another 15,000 at the U.S. border will have limited success in curbing the surge of asylum seekers from Central America.

Sen. John Cornyn (R-Texas) used his index finger and thumb to make a “zero” sign Thursday when asked how much progress had been made in addressing the border challenges. The agreement with Mexico has helped a bit, Cornyn said, but he emphasized that the Mexican government would have to do more.

“It’s a Band-Aid,” Sen. Lindsey O. Graham (R-S.C.) said. “The smugglers and coyotes will find a way around the Mexican army. They’ll bribe people. This is not a sustainable fix.”

A White House official faulted Congress for failing to amend asylum laws, as the administration has requested. “While members continue to ignore their responsibility, other countries can also take significant actions to help,” said the official, who spoke on the condition of anonymity to speak bluntly. “If those countries refuse, however, then the United States will have no choice but to consider travel bans, significant actions on remittances and/or tariffs.”

Trump announced the immigration deal with Mexico on June 7, trumpeting it as a major victory after he threatened to enact tariffs on all Mexican goods. In addition to dispatching the national guard forces, Mexico agreed to work with the Trump administration to expand a program in which asylum seekers at U.S. ports of entry would be required to wait in Mexico as their immigration cases are adjudicated, a process that has stranded thousands of migrants in border towns for months.

But Trump also suggested the deal would eventually include safe third country agreements with Mexico and Guatemala, which immigrant rights advocates have long opposed over concerns about the well-being of migrants in those countries. The only country with whom the United States has such an agreement is Canada.

In June, Customs and Border Protection apprehended 94,000 migrants at the southern border, a 29 percent drop from the 133,000 who were detained in May. Though border-crossings have traditionally declined during hot summer months, Trump administration officials hailed the decrease as evidence that the president’s strategy is working.

The numbers have continued to decrease in July, but the pace remains at “crisis levels,” said a Customs and Border Protection official, speaking on condition of anonymity to discuss the preliminary figures.

A different senior administration official pointed to a significant drop in the number of migrants who were in CBP custody from nearly 20,000 at the end of May to fewer than 8,000 this week as another sign that the administration is making progress. This official noted that Congress approved a $4.6 billion emergency border bill that also will help alleviate strain on the immigration system, though many Democrats opposed the measure over concerns that the money could bolster enforcement efforts.

In announcing the deal with Mexico, Trump said that nation would reassess its efforts after 45 days, a deadline that passed Monday. Mexican officials said they have made major progress in preventing border crossings, and so there is no need to pursue negotiations on the safe third provision, which the government has long opposed.

The White House is convening a meeting Friday to determine next steps, a person familiar with the plan said.

Trump reacted angrily this week to the news that Guatemala’s constitutional court had ruled that President Jimmy Morales must gain legislative approval for a safe third country agreement, discounting the legal ruling as an impediment to a deal.

“Guatemala gave us their word. We were going to sign a safe third agreement and then, all of a sudden, they backed up,” Trump told reporters at the White House on Wednesday. “They said it was their [constitutional] court. I don’t believe that.”

Trump said his administration was looking at doing “something very severe” in response, suggesting new tariffs on Guatemala’s goods and hinting at a potential travel ban on citizens from that nation, which NPR reported Thursday is under consideration.

“Yes he’s serious,” Graham said about Trump’s threat toward Guatemala. “I don’t know what you expect us to do. Right now, there is a never-ending stream coming from Guatemala.”

Analysts said Morales, a lame-duck leader with just months left in office, is eager to sign a deal and will seek to find a way around the court ruling. But they predicted it will be difficult.

The legislature “is not going to be able to jam this through,” said Jo-Marie Burt, an analyst at the Washington Office on Latin America, a human rights group. “I don’t think it’s an overstatement to call it a huge setback.”

Edgar Gutiérrez, one of five ex-foreign ministers who petitioned the Guatemalan court to block Morales from signing a safe third country deal, said he doubted Trump would be able to impose a travel ban or new tariffs because of legal hurdles and bilateral treaty obligations.

“He’s frustrated,” Gutiérrez said in an interview. “So he’s reacting in a furious way.”

On Thursday, the White House vowed to fight a ruling this week from U.S. District Judge Jon S. Tigar in San Francisco, who blocked the administration’s attempt to enact a new regulatory policy to declare migrants ineligible for asylum in the United States if they had first passed through another country where they could have sought refuge instead.

In his ruling, Tigar wrote that the Trump administration’s policy “purports to offer asylum seekers a safe and effective alternative via other countries’ refu­gee processes,” but he said the government offered no evidence that other countries have a comprehensive asylum system.

“It’s clear at this point that the increase in Mexican enforcement has had some effect,” said Aaron Reichlin-Melnick, a policy analyst at the American Immigration Council. “But thousands are still seeking protections every week and there’s no sign that the Mexican enforcement has cut things off at the source entirely.”

Mary Beth Sheridan contributed to this report.