He pointed to the Obama administration policy derided by Republicans as "catch and release".
Despite Sessions' public announcement of the strategy, President Donald Trump has continually heaped blame on Democrats, saying the party must "change their law" to stop the separations. "Not on my watch".
Melania Trump, the most reticent USA first lady since Pat Nixon, has done an admirable thing. "We are enforcing the laws passed by Congress", she said in an appearance before the National Sheriffs' Association in New Orleans. "Change the laws!" he said.
Inasmuch the law that enables authorities to separate families crossing illegally into the USA has been in the books through Democratic and Republican administrations, it is President Trump's (and his Attorney General Jeff Sessions') "zero-tolerance policy" that has resulted in hundreds of children, some of them toddlers, being separated from their parents in heart-rending scenes that had outraged much of America and the world.
While entering the US illegally has been a crime for decades, carrying penalties of six months in jail, it's generally been ignored in favor of treating illegal immigration as a civil matter and attempting to deport those caught.
"It holds Dreamers and kids who have been separated from their parents hostage in order to cut legal immigration and enact the hard right's immigration agenda", Chuck Schumer, the Senate Democratic leader, said in a statement on Monday".
Speaking at the same conference, Sessions echoed Nielsen's defense of the policy, and called on Congress to act. "If we build the wall, if we pass legislation to end the lawlessness, we won't face these awful choices".
Children are being used by some of the worst criminals on earth as a means to enter our country.
Images of children living in converted buildings near the border and tents being erected to house migrants have led to fierce political debate and comments from some unexpected quarters. Voters couldn't agree with her more, and responded to her touching op-ed on Twitter.
His wife, who does not often wade into the political arena, did not denounce his administration´s policy, but instead called for bipartisan immigration reform to fix the issue. "We need borders, we need security, we need safety", Mr. Trump said.
The signs of splintering GOP support are spreading.
His tweets came as senior Republicans continued to call into question the hardline policy.
Also Sunday, at least five people died when an SUV vehicle carrying 14 people went out of control after it was chased by US Border Patrol agents in south Texas.
The child separation policy is a controversial policy aimed at Mexican immigrants who try to enter the United States at illegal border crossings. "That's traumatising to the children who are innocent victims, and it is contrary to our values in this country".