This morning's front-page New York Times story on purges is, I believe, somewhat inaccurate in one potentially significant respect. After describing apparently unlawful purging practices in several states, the article says: "Some states allow such voters to cast provisional ballots."
My understanding of HAVA--and I believe the prevailing understanding in the legal community (of those who focus on HAVA-related issues)--is that HAVA requires every state to let all individuals cast a provisional ballot if they are willing to affirm that they believe themselves to be registered voters, as presumably would occur if there an unlawful or otherwise erroneous purge. The relevant provision is 42 U.S.C. 15482(a). (This requirement is inapplicable to states with Election Day Registration or without any form of voter registration, but the purging problem discussed in the article does not arise in those states.) Thus, any voter wrongly purged should be able to cast a provisional ballot, and it would be a qualitatively different problem on Nov. 4 if any voter who thinks he or she has been wrongly purged is denied a provisional ballot. That's what occurred in 2000, and that's what HAVA's provisional voting mandate was designed to avoid.
Of course, there is a separate question of whether the provisional ballots get counted, as the New York Times article notes. But given the predicate assumption that a voter was purged from a state's voter registration rolls in a manner that violates federal law, either HAVA or NVRA, it would seem that there is a very strong argument HAVA would require the counting of that provisional ballot (unless, perhaps, the review of the provisional ballot turned up some different basis for concluding that the voter was ineligible to vote--for example, being under age 18). HAVA specifically requires states to count provisional ballots if a review of those ballots shows the provisional voters to be "eligible under State law". 42 U.S.C. 15482(a)(4). I've written previously on whether or not "eligible" in this sentence means something different from "registered." See Foley, The Promise and Problems of Provisional Voting, 73 Geo. Wash. L. Rev. 1193 (2005). But regardless of the resolution of that issue, it would seem that if the basis for purging a voter from the state's registration list (and thus deeming the voter not "eligible" to vote) is a basis that violates federal law, then the states would be preempted in this instance from considering the voter not registered under state law--and thus would be required by HAVA to count the provisional ballot.
Contrary to the implication of the New York Times article ("But [provisional ballots] are often not counted because they require added verification."), I don't think it would be tenable under HAVA in this unlawful purging situation to disqualify a provisional ballot for failure to comply with some extra identification requirement applicable to provisional voters (who cast provisional ballots for reasons unrelated to the unlawful purges). If the voter should have been deemed registered (since, by hypothesis, the purge was unlawful), the only ID requirements that could be imposed at the polling place were the ones applicable to all registered voters, who would then cast regular ballots. The unlawfully purged voter should have been considered a registered voter, and thus should be treated as such for purposes of counting the provisional ballot if that voter complied with the ID requirements of a registered voter. If a review of the provisional ballot shows that the voter should have been deemed registered (because the purge was unlawful), and the voter should have received a regular ballot (but for the unlawful purge), then the provisional ballot should be counted as if it were the regular ballot that the voter should have received. Perhaps a more simple way to put the point is this: if what took the voter off the roll was a violation of federal law, then the voter should be treated as if he or she were on the rolls--and HAVA does not permit disqualifying a provisional ballot of a registered voter unless the individual was not entitled to register in the first place, being under 18 for example.
To be sure, it would be better not to have unlawful purges in the first place. (I have no independent knowledge of what the New York Times article describes as unlawful purging is occurring, or is a violation of federal law. I'm assuming the truth of those points for purposes of this analysis.) For one thing, as I and others have observed, a large percentage of provisional ballots complicates the identification of the winner of a close election. And if it does happen that a large number of provisional ballots are cast because of what the New York Times describes, then close attention will need to be paid on how officials in those states conduct their process of reviewing those provisional ballots. But the assumption should not be that unlawful purges will lead to voter disenfranchisement. In fact, if HAVA works as intended, the assumption should be just the opposite: provisional voting will protect voters from disenfranchisement despite unlawful purges.
Thus, whatever they read or hear about problems that state officials may be having in maintaining their voter registration lists, citizens who think themselves registered should go to the polls. If poll workers tell them they are not on the list of registered voters, then they should cast provisional ballots--they should not leave without doing so, and no poll worker should deny them this right. Then, if it turns out they were wrongly removed from the list of registered voters, then HAVA should do its job of making sure that the erroneous purge does not prevent their ballots from being counted as valid votes.