Trump earlier Wednesday said the then-looming action "ultimately will be matched by legislation" after House Speaker Paul Ryan announced the House will vote Thursday on a bill to end the practice.
Meanwhile, the document Trump signed won't reunite the more than 2,300 children now separated from their parents, whose plight Trump admitted privately this week was deeply damaging to him politically.
"It's about keeping families together while at the same time making sure that we have a very powerful, very strong border", Trump said as he signed the order in a hastily arranged Oval Office gathering.
The Trump administration came under intense criticism for its "zero-tolerance" policy after recent images from a detention center in Texas showed children locked up in cages. "Nobody wants to see parents and children separated, but. the blame should be put squarely back on the shoulders of the people who broke the law in the first place".
As distressing images and audio of bereft children emerged, Trump found himself lobbied privately by his wife and elder daughter to do more.
Democrats have said that the situation is Trump's fault, and accused him of using the children as leverage to force them to negotiate on immigration and the president's long-promised border wall. Just in the past week, Trump has gone from saying he won't support the compromise bill to saying he supports both bills; as one Republican said after yesterday's meeting: "He made comments like "I'm behind it 1,000pc, ' but what is 'it"?"
One of them said Nielsen, who had become the face of the administration's policy, had little faith that Congress would act to fix the separation issue and felt compelled to act.
Kansas City, Kan., deputies shot, one dead
Several law enforcement departments offered words of support and prayers for Wyandotte County on social media . The Associated Press reported that one sheriff's deputy had been killed and another was in critical condition.
During the course of the week, governors of the US states of Colorado, Maryland, Rhode Island and NY ordered their state assets such as National Guard personnel or equipment be refrained from being used to support the Trump administration's mission to secure the US-Mexico border.
However, the effort to keep families united would be accomplished in a way that does not seem like a humane solution. The executive order instructs the attorney general to seek federal court permission to modify the consent decree.
They also said families facing lengthy detention under the new executive order will be able to sue the Trump administration outside of the Flores framework. None of them were accompanied by minors or family members. Just in the past few days he had insisted his hands were tied by law on the issue of family separations even though his administration implemented a "zero tolerance" policy. "It's a problem that's gone on for many years, as you know, through many administrations". But immigrant children are only allowed to be held for 20 days, according to a 21-year-old landmark court decision known as the Flores agreement.
The almost 300-page compromise measure creates a path way to citizenship for the young immigrants known as Dreamers, who have been living in the US illegally since childhood. The case has gone through a prolonged and fierce legal battle all the way up to the Supreme Court.
Trump's order, drafted by Homeland Security Secretary Kirstjen Nielsen, directs her department to keep families together after they are detained for illegal border-crossing. In other words, existing cases will not be "grandfathered in" to be covered under the new order, the official said. Health and Human Services (HHS) Secretary Alex Azar has said his department will begin working to return detained immigrant children to their families, but did not give a timeline.
"This Executive Order doesn't fix the crisis", tweeted Sen. "Every child is entitled to basic human rights".
White House Chief of Staff John Kelly was blunter when he talked about the deterrent effect of separating families in a CNN interview as secretary of homeland security previous year.