Look, I expect authoritarians to have trouble grasping the US Constitution. When you have no intention of obeying a law that limits your authority, there's a built-in incentive to misunderstand -- or at least pretend to misunderstand -- that law (cue Nancy Pelosi on questions about limits to Congress's constitutional authority: "Are you serious? Are you serious?").
But it really bugs me when libertarians, especially libertarians who stress and emphasize strategies like Bill of Rights Enforcement, either misunderstand or just flat ignore significant parts of both the Bill of Rights and the rest of the US Constitution. Like this:
The present occupant of the White House has illegally usurped the power to grant "executive amnesty" to tens of millions of foreigners either in the United States illegally, or about to come.
Let's hit the Bill of Rights portion first and work backward on the "illegally" part:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
That's the last sentence of the Bill of Rights and its meaning is not unclear. If the Constitution doesn't delegate a power to the federal government, the federal government doesn't have that power. Period.
So, does the Constitution delegate the power to regulate immigration to the federal government?
No. And not only no, but it specifically and unambiguously prohibits that power to the federal government. Here's Article I, Section 9:
The Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred and eight, but a Tax or duty may be imposed on such Importation, not exceeding ten dollars for each Person.
The framers considered this clause important enough (probably because the Constitution wouldn't have been ratified without it) that in Article V they prohibited even amending it out of the Constitution before 1808 ... which establishes beyond reasonable doubt that after 1808, the only way to create the power alluded to is to amend it.
Feel free to go and find the amendment in question. I'll wait ... OK, are you back? Didn't find it, did you? That's because it's not there. Congress can charge immigrants ten bucks, but that's the entirety of constitutional federal power vis a vis immigration; nobody even bothered pretending any more power than that existed until the 1870s when an activist Supreme Court started fantasizing such things into the Constitution.
There's no such thing as an "illegal alien."
BUT! Just this once, for the sake of argument, I'm going to pretend that history didn't happen the way it did, that the framers didn't explicitly (and for stated reasons after considerable argument) prohibit the federal government from regulating immigration. I'm going to pretend that so that I can address US President Barack Obama's "illegal usurpation" in the form of "amnesty" to people who are in the US "illegally." Here's another section of that pesky Constitution:
The President shall ... have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.
Once again, there is no such thing as an "illegal alien." But if there was, the president of the United States would be entirely within his constitutional authority to pardon or reprieve any or all such "illegal aliens."
Yes, it really is that simple.