@athairmor@lemmy.world is right; presidents cannot pardon state level crimes: https://constitution.congress.gov/browse/essay/artII-S2-C1-3-1/ALDE_00013316/
Specifically, the offense must be “against the United States”, and state level offenses are only against the respective state, not the United States.
Their plan is to claim that the children of undocumented immigrants are somehow not “subject to the jurisdiction” of the United States and therefore not granted citizenship based on the 14th amendment.
Yes, it really is as stupid as it sounds; claiming that undocumented immigration gives your descendants the equivalent of diplomatic immunity.