Speaker Pelosi thinks she has the power not to seat a duly elected member of the House.
She’s wrong, and that’s not just my opinion. The Supreme Court has already ruled the Speaker, indeed the whole House, does not have that power. Powell v. McCormack, 395 U.S. 486 (1969). Unless the House can show that the winner of an election does not meet the constitutional qualifications for office (for example, isn’t at least 25 years old or isn’t a resident of the state represented), the member must be seated.
Once a member is seated, he or she can be expelled, but that requires a 2/3 vote. Pelosi doesn’t have the supermajority necessary to expel Mariannette Miller-Meeks, so she doesn’t appear to have a lawful means of stealing the Iowa Second District seat for the Democrats.
Of course, that doesn’t mean that the arrogant overreach that has been on display thus far this session won’t lead her to do something foolish.