Then the courts were absolutely wrong. Just the way they’ve been wrong pretending that a child born in the US to illegals is a US citizen.
The idea that the rights enumerated in the Constitution of the US applies to people here illegally is suicidal and against and opposed to the very principles upon which the Constitution is founded.
Perhaps so, but the courts have held otherwise which means that it's not constitutional to willy nilly load a bunch of people you suspect are here illegally on a bus and transport them back to their home country.
We're a nation of laws and a president or any one else, for that matter, doesn't get to pick and choose which ones to obey based on personal beliefs or preferences.
Trump knows this and he's just demagoguing the issue.
The quickest and most efficient way to "reform" our immigration system is to put people in office who will actually enforce the laws on the books. We haven't had a president or congress willing to do that for decades.