The labor union for federal asylum officers is condemning President Trump's policy of sending migrants to Mexico as they wait for their assigned court dates in the U.S., calling the Trump administration's program "fundamentally contrary to the moral fabric of our Nation."

The asylum officers, who are tasked with carrying out a policy widely known as "Remain in Mexico," said they have a duty "to protect vulnerable asylum seekers from persecution," and that Trump's policy creates a conflict between their professional responsibility and the president's directives.

Writing in a briefin support of a federal lawsuit seeking to halt the program, the union representing asylum officers say the policy formally known as the Migrant Protection Protocols is a "widespread violation" of international and domestic law.

The American Federation of Government Employees Local 1924 tells the Ninth Circuit Court of Appeals in California that the MPP program does not allow for all applicants to be asked whether they fear persecution in Mexico, and only provides for that discussion if the applicant raises it.

The union filing also says the standard for judging whether the applicant is in real danger is too high, that asylum seekers are not provided with lawyers to help them through the process, and that "Mexico is simply not safe for Central American asylum seekers."

In addition, administering the program diverts limited resources away from interviewing asylum seekers, the filing says, and therefore exacerbates problems at the border, including worsening what is already a long backlog of pending asylum cases.

"[The Migrant Protection Protocols program] violates our Nation's longstanding tradition and international treaty and domestic obligation not to return those fleeing persecution to a territory where they will be persecuted," the asylum union writes in the legal brief.

The union writes in the filing that helping advance the Migrant Protection Protocols could place the lives of migrants hoping to win asylum back into danger, which is "something that they did not sign up to do when they decided to become asylum and refugee officers for the United States government," according to the asylum workers' filing.

In a separate friend-of-the-court brieffiled Wednesday, former U.S. officials, including Janet Napolitano, who served as Secretary of Homeland Security in the Obama administration, and James Clapper, former U.S. Director of National Intelligence, write that the Trump program violates international commitments.

"Violating this obligation does more than place these particular migrants in harm's way—it threatens the foundation of the international refugee system, which depends on cooperation between countries that cannot be sustained in the face of flagrant violations under the MPP," the former federal officials write.

They argue to the appeals court that there is "no evidence" that asylum seekers pose a security risk to American citizens, nor is there any basis for the claim that migrants who apply for asylum are smuggling illegal drugs over the border.

A federal judge initially blocked the program, but in May, the Ninth Circuit overruled the lower court and allowed the program to continue. The American Civil Liberties Union and other groups are challenging the policy that has sent many thousands of migrants back to Mexico since January.

Trump has long slammed what he calls catch and release policies, where migrants seeking asylum are released into the U.S. while they wait for their immigration court hearings.

The filings come as Trump officials push Congress to pass $4.6 billion in aid to address humanitarian problems at the border. The Republican-led Senate passed a bill on Wednesday a version of the emergency border aid. The bill advanced the same day lawmakers in Washington fielded questions about a disturbing photo of a father and daughter. The pair are face-down, having drowned attempting to cross the Rio Grande, fleeing poverty in El Salvador.

In the face of Trump's crackdown on border crossings, the flow of migrants across the country's southern border has not slowed. In fact, border crossings have accelerated recently.

In May alone, according to Customs and Border Protection, the number of apprehensions along the U.S.-Mexico border exceeded 144,000, the highest one-month total in more than a decade. Many of the migrants are escaping violence and poverty in Central America.

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