[Editor’s Note: This post was originally published on the American Civil Liberties Union’s blog, Washington Markup, on June 3. If you represent a national organization, please sign this letter being circulated by CHN urging President Obama to end the practice of family detentions.]

Secretary of Homeland Security Jeh Johnson announces the opening of a new “family detention” center in Dilley, Texas, for adults who cross the U.S.-Mexico border with their children.

One third of the Senate has had enough of the Obama administration’s abusive imprisonment of vulnerable mothers and children fleeing violence in Central America. In a letter to Homeland Security Secretary Jeh Johnson on Monday, they wrote:

“We urge you to end the practice of presumptive detention of families and return to the policy of utilizing detention only as a last resort, when there is a serious public safety or flight risk that cannot be mitigated by alternatives to detention.”

The letter was signed by 33 senators — an overwhelming majority of the Senate Democratic caucus. They join the 136 House members who last week sent a letter to the DHS secretary, urging for an end to family detention. President Obama is now at odds with the majority of the Democratic congressional caucus, who are criticizing his administration’s use of detention to deter mothers and children from seeking asylum in the United States.

The congressional letters were sent at a critical time, as the Department of Justice is working under court-imposed deadlines to negotiate the future of the administration’s family detention policies. In May, a federal judge concluded in a tentative ruling that detaining children with their mothers in secure and unlicensed family detention facilities violates the 1997 Flores v. Reno settlement agreement, which governs the housing and care of migrant children. DOJ and the children’s counsel now face a June 19 deadline to report to the court on the results of their negotiations. If they cannot reach an agreement, the judge could issue a final ruling that would have sweeping implications on the administration’s family detention policies.

Once an almost abandoned practice, family detention has surged since summer 2014 as DHS has ramped up its family detention capacity from fewer than 100 beds to an anticipated 3,700 beds by 2016. Most of the Central American families detained by DHS have come to the U.S. seeking refugee protection, having fled one of the most dangerous regions in the world where women and children are raped, abused, and killed with impunity. Eighty-eight percent of detained families have demonstrated to a DHS asylum officer that they have a credible fear of persecution if deported.

Since the summer of 2014, the ACLU has been working to halt the administration’s family detention practices. In February, a federal judge issued an order in RILR v. Johnson, an ACLU class action suit challenging DHS’s policy of detaining families seeking asylum, in order to deter future migration from Central America. The court blocked DHS from relying on general deterrence as a basis to detain families. While DHS is technically complying with the order DOJ continues to fight the RILR case in court.

Multiple ACLU lawyers have visited all the family detention facilities, including the mega facility in Dilley, Texas, which will detain up to 2,400 children and mothers at maximum capacity. ACLU prison expert Carl Takei recently returned from Dilley and was greatly disturbed by the “barracks-like structures that offer no privacy — a single room can hold as many as 12 people… [but] no toilets or showers inside the housing units.” Takei goes on to describe how Dilley reminded him of Manzanar, Tule Lake, and other World War II prison camps that locked up Japanese-American families.

“We do not believe there is any system of mass family detention,” the senators wrote to DHS Secretary Johnson, “that will work or is consistent with our moral values and historic commitment to provide safe and humane refuge to those fleeing persecution.”

The writing is on the wall — DHS may not lawfully detain children and parents together in detention camps. It’s time President Obama took note and did the right thing.

[Photo Credit: Official DHS photo by Barry Bahler]