The court didn't order the release of immigrant parents with the children but didn't forbid it, either. "That's traumatising to the children who are innocent victims, and it is contrary to our values in this country".
Trump and others in the administration have blamed the separations on a law the president claims was written by Democrats. Anita McBride, executive-in-residence at the Center for Congressional and Presidential Studies at American University in Washington and a former chief of staff for Bush, said Monday these first ladies are well-known for standing up for women's issues.
Former first lady of the United States Laura Bush has launched a scathing attack on President Donald Trump for implementing "zero-tolerance policy" towards illegal immigrants. "Jesus said suffer the little children unto me - he did not say let the children suffer".
In a rare comment, Mrs Trump spoke against the Trump administration's harsh policy, saying the U.S. needs to be "a country that governs with heart". Melania Trump, the first lady, also appeared to question the treatment of migrants.
"I visited Thailand and witnessed firsthand the trauma of parents and children separated by circumstances beyond their control", the statement said.
In an effort to rebut criticism of the administration, Homeland Security Secretary Kirstjen Nielsen on Sunday repeated in a tweet the department's view: "We do not have a policy of separating families at the border".
In a blog written on The Washington Post, Laura Bush who served as the First Lady of the USA from 2001 to 2009 termed the policy "cruel", "immoral" and "heartbreaking". The administration put the policy in place and could easily end it after it has led to a spike in cases of split and distraught families.
The number of separations has jumped since early May, when Attorney General Jeff Sessions announced that all migrants illegally crossing the USA border with Mexico would be arrested, regardless of whether the adults were seeking asylum.
"I would like to take one minute and say something directly to President Trump", he said in a Monday interview on Fox News' "Fox & Friends".
"We must either release both the parents and children - this is the historic get out of jail free practice... or the adult and minor are separated as a result of prosecuting the adult".
Mrs Trump, who moved from her native Slovenia to the U.S. where she married her husband in 2005, often campaigns on behalf of children. Every Senate Democrat is on board with the legislation, but they need Republican support in order to pass it.
Bush's op-ed comes on the heels of current first lady Melania Trump's spokeswoman weighing in on the issue on her behalf.
"Mrs Trump hates to see children separated from their families and hopes both sides of the aisle can finally come together to achieve successful immigration reform", her communications director, Stephanie Grisham, told CNN.
One would limit, but not entirely prohibit, family separations, fund Trump's wall and give legal protections to young immigrants, known as "Dreamers", who were brought to the country illegally as children. GOP Sen. Susan Collins also expressed concern.