A group of more than 140 House Democrats led by Rep. A. Donald McEachin (D-Va.) sent a letter to President Trump asking him to “reconsider the ill-advised and indefensible policy” of reinstating the military’s ban on transgender service members.

In the memo he signed on Friday, which has since been delivered to the Pentagon, President Trump directs Defense Secretary Jim Mattis to determine whether to remove already enlisted transgender individuals from service. It also bars the military from funding gender confirmation surgery.

“In my judgment, the previous Administration failed to identify a sufficient basis to conclude that terminating the Departments’ longstanding policy and practice would not hinder military effectiveness and lethality, disrupt unit cohesion, or tax military resources, and there remain meaningful concerns that further study is needed to ensure that continued implementation of last year’s policy change would not have those negative effects,” the presidential memorandum reads.

Four days after Trump signed the memo, the group of House Democrats have expressed their opposition to the measure in a letter to President Trump dated Aug. 29, which slams the president’s claim that transgender service members are a hindrance to the U.S. military’s effectiveness. The group claimed that the ban, which the Obama administration lifted in June 2016 after it was a longstanding policy, is unconstitutional.

“We urge you to reconsider your ban on transgender individuals serving in our country’s military. There is no place for discrimination in our Armed Forces or indeed anywhere else in American society. Enforcing your ban could mean discharging active duty soldiers, sailors, Marines, and members of the Air Force who are serving honorably. It also would mean barring other patriotic Americans from serving in the future. Both actions are detrimental to our national security, ill-advised, and contrary to the values upon which our nation was built,” they wrote.

A July 2017 deadline was set for determining whether transgender people could be allowed to enter the military, but Mattis delayed that to Jan. 1, 2018, and Trump has now instructed him to extend it indefinitely. However, there have been news reports that cite a White House official claiming that Mattis must implement the new policy by March 23, 2018.

“Implicitly, your ban denies the value of transgender servicemembers, and it questions the professionalism of those who serve beside them,” the letter from the Democrats reads. It also suggests that the President’s memo was a rash decision, saying it was made without proper consultation with top national security or defense officials.

President Trump signed the controversial executive memo as Hurricane Harvey, now a Category 4 storm, tore through southwest Texas.

“We urge you again to join us in honoring all those who protect our nation; to fully respect the rights of the citizens you serve; and to reconsider the ill-advised and indefensible policy that you have moved to implement,” the letter implores.

Among the Democrats to sign the letter Tuesday were House Minority Whip Steny Hoyer (Md.) and Rep. Joe Crowley (N.Y.), the chairman of the House Democratic Caucus.

The President’s directive came after Trump announced last month in a tweet that he would reinstate a ban on transgender military service that ended last year under the Obama administration.

The decision has spurred criticism from lawmakers from both sides of the aisle, while many social conservatives have praised the move.

This policy is a shameful slap in the face to people who put their lives on the line everyday to defend our country…” said Jennifer Levi, an official at Glad (GLBTQ Legal Advocates & Defenders), in a statement. “We are moving quickly with our plaintiffs to see that a court puts a stop to this latest demonstration of President Trump playing politics with people’s lives.”

Carl Tobias, a legal expert at the University of Richmond’s School of Law, said, “Trump seems to be granting Mattis discretion to decide which currently serving transgender people can continue to serve. It appears that Mattis has discretion substantively and procedurally.”

The White House official on Friday said Trump also directed Mattis to halt the use of federal funds to pay for sexual reassignment surgeries and medications, except in cases where it is deemed necessary to protect the health of an individual who has already begun the transition. That policy is to be written within six months and implemented by March 23.

In his directive to Mattis, Trump said he found that his predecessor’s transgender policy was flawed.

“In my judgment, the previous administration failed to identify a sufficient basis to conclude” that ending the longstanding ban on transgender service would not “hinder military effectiveness and lethality” and be disrupting in the ranks, he wrote.

Dana W. White, the main spokeswoman for Mattis, issued a two-sentence statement saying Mattis had received White House guidance on transgender policy, adding, “More information will be forthcoming.”

It was just one year ago, in June 2016, that then-Defense Secretary Ash Carter announced that transgender individuals could serve openly for the first time. Prior to that, most transgender people in the military had been forced to keep their status secret to avoid being discharged.

Since Carter’s policy change, some troops — possibly a couple hundred — have openly declared their status as transgender individuals.