Thousands of ballots are at stake as the Supreme Court considers Pennsylvania voting rules

Pennsylvania’s mail balloting policies have been the focus of intense litigation since the 2020 election. Now, two new cases may address the rules in the biggest battleground state on the eve of the election, with implications for thousands of ballots that have already been mailed in or dropped off.

The latest fights — and there may be more to come — present two issues. The first case is about whether a voter who returns a “deficient” mail ballot — for example, a mail ballot missing its “secrecy envelope,” or one that was undated or misdated by a voter — can cast a provisional ballot instead on Election Day, as was the general practice in 2022. The state Supreme Court recently said yes, based on state law, but the U.S. Supreme Court may soon weigh in. The NBC News Decision Desk estimates that thousands of votes could be at stake.

The second case is about whether undated or misdated mail ballots should be rejected at all. That issue has been litigated many times, because election officials do not use the date written by a voter on the ballot envelope to determine the validity of a mail ballot — they just consider if the mail ballot was received on time. Previous suits have not succeeded in striking down the state rule, but a Pennsylvania appellate court revived the issue on Wednesday by requiring the Philadelphia Board of Elections to count undated and misdated mail ballots in the context of a September special election.

And while it’s not clear whether that decision will prompt a reassessment of the statewide rule for the 2024 presidential election — the state Supreme Court had previously indicated they are unlikely to change the rules while voting is underway — the NBC News Decision Desk estimates there could be thousands of misdated or undated mail ballots in Pennsylvania.

Mail balloting issues are especially important in Pennsylvania, given the 19 electoral votes up for grabs in the state, the closeness of the race, and the fact that Democrats disproportionately vote by mail there. Here is what’s at stake in the battleground state — and the data and process behind those ballot estimates.

The background: The many ways voters can mess up their mail ballots in Pennsylvania

Voting by mail in Pennsylvania is rife with opportunities for voter error. To vote by mail in the state, a registered voter must request a mail ballot and return it by Election Day. But there are essentially three main reasons the state rejects mail ballots even if they are received on time. Specifically, Pennsylvania rejects mail ballots if the voter did not sign or date the affidavit on the outside of the return envelope or did not enclose the ballot in an inner secrecy envelope.

Together, Pennsylvania’s mail ballot rules have generated an entire vocabulary for rejected mail ballots — ballots that are unsigned, undated or misdated, or even “naked,” if they are not clothed in a secrecy envelope.

To complicate matters, Pennsylvania does not have a common policy for notifying voters of a mail ballot error or offering voters opportunities to correct them. In the 2022 general election, some counties published lists of voters with deficient mail ballots and some did not notify voters at all. Meanwhile, some voters were able to correct their mail ballots and get them counted, while others were directed to vote provisionally on Election Day, having the provisional ballot count instead. 

Digging into the number of ballots affected so far

Using newly released data for 2024 and previous data from 2022, we can estimate the number of votes that may be at issue under various scenarios in Pennsylvania, depending on how the court cases play out.

Estimating the number of mail ballots that have been rejected and fixed to date in the 2024 election starts with new information provided by Pennsylvania’s secretary of state. On most days, the state makes public the status of every mail ballot. 

The latest update from Oct. 31 — after the general statewide deadline to request a mail ballot — shows there were 2,193,578 mail ballot applications ever approved. Of these, 1,622,675 have been logged by local election officials as returned, which means about a quarter are still outstanding.

Of these returned mail ballots, 5,059 would not count under current law: 2,050 are currently unsigned, 2,254 are misdated or undated, and 755 are naked.

Further, in some Pennsylvania counties, the data show that voters who previously returned a deficient mail ballot have already been able to correct the error. Voters have fixed 1,151 mail ballots which previously had signature errors, 1,846 which previously had date errors, and 347 which were previously naked.

Importantly, the latest mail ballot data is more up to date in some counties than in others. In general, Pennsylvania forbids counties from opening up mail ballots before Election Day. However, counties can engage in what’s known as “pre-canvassing” — identifying a mail ballot with a deficient affidavit or missing secrecy envelope without opening it, since the affidavit is on the outside of the mail ballot return envelope.

Some counties have also adopted a special mail ballot return envelope with a pre-punched hole, so they can confirm whether that inner secrecy envelope is there without opening the return envelope. 

Ultimately, some counties pre-canvass mail ballots for any affidavit or secrecy envelope issue, some only pre-canvass for affidavit issues, and some do not pre-canvass at all. By definition, that means the latest statistics understate the extent of mail ballot errors, because they do not include mail ballots which have errors that are yet to be discovered since they have not been pre-canvassed. 

Estimating the full number of affected ballots

To estimate the total number of problematic mail ballots, including those missing from the statewide data, the Decision Desk focused on the 27 counties which appear to pre-canvass both the secrecy envelope and affidavit on mail ballots and the 17 counties which pre-canvass only the affidavit, counting the number of mail ballots that have been flagged as problematic in any of the state’s daily updates.

For example, in a pre-canvassing county, a voter may have returned a deficient mail ballot on Oct. 15 and subsequently corrected the error in a county office by Oct. 22. In a county which does not pre-canvass, we’d expect that same ballot to be canvassed and rejected on Election Day.

In the counties that appear to be pre-canvassing both the affidavit and the secrecy envelope, about 0.8% of mail ballots returned ever had an issue across any of the state’s daily updates. 

More specifically, about 0.13% of mail ballots returned ever had a secrecy envelope issue, 0.31% had a signature issue, and 0.39% had a date issue.

The counties that only partially pre-canvass show slightly fewer errors: 0.20% and 0.27% of mail ballots returned ever had a signature or date issue, respectively.

Applying these percentages to the returned number of mail ballots that have not been pre-canvassed throughout Pennsylvania, that suggests there are about another about 2,500 mail ballots already returned that will otherwise be rejected. Combined with the deficient returned ballots that we already know about referenced above, that comes to about 8,000 deficient mail ballots that have been returned to date.

Still, those estimates are tentative, since more mail ballots will be returned in the coming week. Thus far, only about 75% of the requested mail ballots have been returned. In comparison, about 89% of requested mail ballots were returned in 2022.

Importantly, mail ballots returned closer to Election Day are more likely to have errors. In general, younger voters and voters with less experience voting by mail are more likely to return their mail ballots closer to the deadline — and those voters are more likely to make errors. In fact, in 2022, the youngest voters and more inexperienced voters were almost twice as likely to return a deficient mail ballot as older or experienced voters.

To get a sense of what the final picture on mail balloting may look like — including provisional ballots on Election Day — it’s helpful to review Pennsylvania’s 2022 general election.

Overall, accounting for incomplete reporting, the best estimate is that about 1.5% of mail ballots were rejected in 2022 because of an issue with the affidavit or secrecy envelope. That estimate is based on similar individual-level data from the Pennsylvania secretary of state, plus supplemental data from individual counties which failed to consistently log mail ballot rejections. We also found that at least 2,200 voters were able to avoid disenfranchisement after returning a deficient mail ballot by casting a provisional ballot on Election Day. 

Although this general election will likely see more mail ballots returned than the previous midterm, the trend so far suggests we might have fewer mail ballots rejected. If about 2,000,000 mail ballots are ultimately returned, then we would tentatively expect 16,000 problematic mail ballots (if 0.8% are deficient)—but it may be more, considering that mail ballots returned closer to Election Day are more likely to have errors and the daily updates provided by the state may still be incomplete or lag local data. Moreover, the experience in 2022 suggests there will also be thousands of provisional ballots cast by voters who return deficient mail ballots. 

In 2022, about 78% of mail ballots supported the Democratic candidate for Senate; so far, the early vote this year appears to be more balanced by party. If the margin of victory in Pennsylvania in 2024 is similar to the margin of victory in 2020, mail ballots will not be the difference. But in a particularly close contest, every vote will matter.

This story first appeared on NBCNews.com. More from NBC News:

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