There's an argument making the rounds that Congress never had the authority to set immigration policy to begin with. Naturalization, yes; that's explicit. But deciding who gets to cross the borders in an inbound direction? Naw.
Seems to me that control of borders and immigration is a requisite characteristic of a nation-state, and is tied in with powers that definitely are assigned to Congress, such as those relating to the common defense.
If immigration must be unrestricted, and borders open, let's try on a scenario: a large group of Canadians crosses the border in a group, all dressed alike and apparently staging an Open Carry event, and not violating any state laws in the process. Can federal authorities do nothing about it until they actually commit a crime against the U.S., like setting fire to the White House?
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