Performing your Constitutional duty as a Member of Congress to certify the results of the electoral college cannot be an act of insurrection. If a Democratic Congress passes something this egregious (which they won't), there's no way SCOTUS allows it.
No, the congressional authority to expel & the invocation of Section 3 of the 14th Amendment would clearly constitute a nonjusticiable political question. After all, the one time that it was invoked in such a manner as Democratic representatives like Cori Bush are proposing today was on the basis of a house of Congress' power to determine the qualifications of its members, something which the Courts have since determined in
Powell v. McCormack that a chamber can give effect to through its power to expel. If the requisite 2/3rds majority of Congress needed to expel a member existed & summarily voted to do so on the basis that such a member's vote against certification of the Electoral College results constituted an "engage[ment] in insurrection," then that'd really be the plain-&-simple end of it. The courts wouldn't get to butt in & say "well, we agree that Congress has this power since the Constitution specifically says that they have this power, but we don't like that they exercised it in this instance," especially when the Constitution doesn't even define what technically constitutes an "insurrection" for the purposes of its invocation. Given all of this, I just don't see how this wouldn't play out similarly to (if not as a repeat of)
Nixon v. United States, with the courts determining that they have no jurisdiction to review the expulsion of a member of Congress & the permanent disqualification thereof on the basis of Section 3 of the 14th Amendment since the Constitution reserves those functions to a coordinate political branch (in this case, Congress).
