The Constitution doesn't say it explicitly but SCOTUS ruled on it in 1898, aliens on U.S. soil (illegal or otherwise) do have the right to due process. Which only makes sense since it prevents the federal government from randomly snatching foreigners off the streets and locking them up just because the feel like it. It also prevents some government flunky from declaring a foreigner on U.S. soil as "illegal" just because he/she doesn't like the way they look.
That of course doesn't mean that foreigners can't be DENIED ENTRY without due process, since the 5th Amendment doesn't apply to foreigners who are not on U.S. soil.
I know. But the scotus doesnt have the legitimate power to create constitutional powers. Does we the people mean people here illegally?
SCOTUS didn't create any constitutional powers with this one, it merely clarified the application of the Bill of Rights and no "we the people" doesn't mean people here illegally but you cannot determine whether or not someone is here legally or illegally without due process, unless of course you abandon the rule of law in favor of the rule of men.
When someone is in pittsburgh, sure. When someone is running across the border, no
The rule of law doesn't work that way, Border Guard Joe Blow playing judge, jury and executioner under ANY circumstances that doesn't involve him defending himself or another non-aggressive person is contrary to the whole idea of the rule of law.
Running across the border doesn't make one an illegal alien, it's just suspicious and under our system of justice it takes a judicial authority to determine whether or not that suspicious activity is illegal or not, what needs to be done is to make the due process in these cases more efficient and more effective.