We have a law. Its being deliberately ignored.
Can you lay out for us here exactly what laws the current administration is ignoring?
Well, for starters, how about this one?
6 USC Chapter 1, Subchapter IV, Part B: "U.S. Customs and Border Protection"
[...]
(2) ensure the interdiction of persons and goods illegally entering or exiting the United States;
[...]
(5) detect, respond to, and interdict terrorists, drug smugglers and traffickers, human smugglers and traffickers, and other persons who may undermine the security of the United States, in cases in which such persons are entering, or have recently entered, the United States;
(6) safeguard the borders of the United States to protect against the entry of dangerous goods;
(7) ensure the overall economic security of the United States is not diminished by efforts, activities, and programs aimed at securing the homeland;
(8) in coordination with U.S. Immigration and Customs Enforcement and United States Citizenship and Immigration Services, enforce and administer all immigration laws, as such term is defined in paragraph (17) of section 1101(a) of title 8, including—
(A) the inspection, processing, and admission of persons who seek to enter or depart the United States; and
(B) the detection, interdiction, removal, departure from the United States, short-term detention, and transfer of persons unlawfully entering, or who have recently unlawfully entered, the United States;
[...]
I could really copy and paste the whole statute here.
Oh, and I realize a large part of your shtick is playing up the partisan angle of most of these discussions, but its most definitely not just the current administration. Both parties have been derelict in this particular duty for quite some time.