The President will take that sharp message on Tuesday evening to a meeting of House Republicans at the Capitol, trying to rally them to get behind a piece of immigration legislation, which could solve a series of issues.
GOP leaders though have been trying for months to figure out a deal, but have found the party too splintered over what to do on DACA, younger illegal immigrant "Dreamers," and ways to tighten what Mr. Trump says are odious loopholes in immigration law.
"A county without borders is not a country at all,' the President declared, as he said that illegal immigrants are bringing "death and destruction" to America.
"They are thieves and murderers and so much else," Mr. Trump added.
But Mr. Trump's criticism of Democrats and Congress has drawn more opposition in recent days from within his own party, who feel the White House is wrongly trying to use the plight of immigrant children to force through immigration law changes.
"President Trump has chosen to implement this policy and he can put an end to it," said Rep. Ileana Ros-Lehtinen (R-FL), "but he chooses not to do so and instead blames others."
"The administration has the power to rescind this policy. It should do so now," said Sen. John McCain (R-AZ) via Twitter.
While Mr. Trump has repeatedly blamed Democrats for the separation of families, it was the Trump Administration that decided to take this step in early May, by prosecuting adults for illegally entering the country.
That move to enforce the law triggers a situation in which children are removed from their parents, leading to the uproar of recent days.
"This is the Trump administration’s policy," said Sen. Dianne Feinstein (D-CA). "President Trump could put an end to this immoral policy right now."
Republicans have floated various ideas in recent days - it wasn't clear if any could make it through the House, as immigration has vexed GOP lawmakers for years, as this latest battle has turned up the heat even more.
"It’s not good policy to separate children at our border from their parents & release them into the US," said Rep. Lee Zeldin (R-NY). "It’s also not good policy to just immediately release an entire family together into the US when that family enters our country illegally."