Last week, a flurry of litigation in Pennsylvania clarified the rules for mail balloting there. In short, mail ballots will still be rejected in the key battleground state if voters fail to properly date the affidavit that accompanies their ballot — but voters who make any mistake with their mail ballot will be able to vote by provisional ballot instead on Election Day.
The NBC News Decision Desk examined how many mail ballots remain outstanding in the state, as well as how many have already been identified by counties as deficient. In the event of a close race in Pennsylvania, provisional ballots and their counting will be getting a lot of attention after Tuesday night.
Voters with outstanding mail ballots will need to ensure that election officials receive their ballots by 8 p.m. Tuesday in order for them to count. But voters with outstanding or deficient mail ballots can also go to their polling place to vote in person.
The data make clear that most provisional ballots will likely come from voters with outstanding mail ballots, rather than voters who’ve already returned a deficient mail ballot. And they also make clear that those provisional ballots may favor Vice President Kamala Harris and her party.
The data on mail ballots and potential provisional ballots
Overall, about 2.2 million Pennsylvanians have had an approved mail ballot application, according to public data from the Pennsylvania secretary of state. So far, about 82% have returned their mail ballot, per the latest figures on Monday. That means there are roughly 390,000 mail ballots outstanding.
If Pennsylvania’s 2024 election follows the same trend we observed in 2022, that means approximately 150,000 more mail ballots will arrive in time to be counted, either via the mail or a drop box. The remaining people with outstanding mail ballots will need to vote in-person on Election Day to have their vote count. If these voters show up and surrender their mail ballot, they could vote with a regular ballot; if not, they’ll vote with a provisional ballot, which election officials will count only after confirming the initial mail ballot was not counted.
In 2022, about a third of voters who requested but did not return their mail ballot ultimately voted in person. Taking 2022 as a guide, we’d expect around 90,000 to vote in-person, with about 35,000 using provisional ballots.
Given that the outstanding mail ballots are disproportionately held by registered Democrats, we expect these provisional ballots to net Democratic candidates some additional votes that will not be reflected in vote totals until a few days after Election Day.
It is more difficult to estimate how many mail ballots will be rejected once election officials start to canvass them tomorrow. Not only does Pennsylvania reject mail ballots if voters did not sign or correctly date the affidavit on the outside of the return envelopes or enclose the ballots in inner secrecy envelopes, but Pennsylvania also forbids counties from “canvassing,” or opening up, mail ballots before Election Day.
Some counties identify mail ballots with deficient affidavits or missing secrecy envelopes before Election Day without opening them, but some leave the task for Election Day. As a result, in some counties we cannot tell the true status of mail ballots.
Overall, our panel of the available statewide data by day show 5,524 deficient mail ballots as of Monday — 2,258 are missing a signature, 2,471 are missing a date or are misdated, and 795 lack a secrecy sleeve. The data also show that about 4,400 voters have taken advantage of county-specific polices to “cure,” or fix, their problematic mail ballot.
In counties where we expect election officials have checked mail ballots returned to date for any affidavit or secrecy issue, about 0.8% of mail ballots have ever been recorded as deficient. If that holds true, we’d expect a little less than 20,000 deficient mail ballots statewide — but the deficiency rate may be higher in other counties.
Voters who have returned a deficient mail ballot and have yet to fix it can vote on Election Day, typically by provisional ballot. These provisional ballots will be counted, per the state Supreme Court’s decision last week.
However, at least in 2022, relatively few voters took advantage of this option. Meanwhile, as mentioned above, an estimated 35,000 might cast a provisional ballot after having not returned their mail ballot at all.
Looking ahead, we expect there to be a lot of discussion on election night and the days after about provisional ballots cast by people who had requested mail ballots. There may well be future litigation revisiting, yet again, whether to count provisional ballots cast by people who previously returned a deficient mail ballot.
But from the perspective of the margin of victory in Pennsylvania, it’s important to keep in mind that many more provisional ballots will be cast by people who never return their mail ballot at all — meaning those ballots are free from any legal uncertainty.