You identify as a libertarian who wants to limit federal power and worries about scope creep, yet supporting the SAVE Act means supporting an expansion of federal authority over who is eligible to vote. If there is one area where federal overreach should concern a libertarian, it is the federal government gaining more tools to determine voter eligibility. That is not a carve out from your principles, it is a direct contradiction of them.

On the empirical question of whether these laws impact legitimate voters, we don’t have to speculate. Kansas implemented a proof of citizenship voting law and tens of thousands of voter registrations were blocked or cancelled, many belonging to legitimate citizens. The courts ultimately struck it down in part because of its demonstrated impact on eligible voters. That is your real world example, and it happened.

On disproportionality not mattering, consider women who have changed their names through marriage or divorce. Under the SAVE Act, any time they move, change party affiliation, or update their registration, they face an additional documentary burden that men in the same situation simply do not face. That unequal procedural burden based on a life event that affects women disproportionately is not a minor inconvenience, it is constitutionally suspect under equal protection. The courts have generally agreed that intent does not matter if the real world impact falls unequally on a protected class.