Pennsylvania — an important swing state — is pleading with the state's Supreme Court after the USPS said it couldn't guarantee on-time delivery of mail-in-ballots

• The US Postal Service recently told the Pennsylvania secretary of state that some election ballots might not be delivered on time because the USPS' delivery standards couldn't accommodate the state's tight election deadlines, The Philadelphia Inquirer reported.
• Pennsylvania's Department of State has now asked the state Supreme Court to allow for mail ballots to be counted if they're received up to three days after Election Day.
• If approved, that means the winner of the presidential race in the swing state may not be known until days after November 3.
• One percent of the state's 1,460,700 primary mail-in ballots this year were rejected because they were late, NPR reported.

Pennsylvania's Department of State has asked the state Supreme Court to allow for mailed-in ballots to be counted if they're received up to three days after Election Day, The Philadelphia Inquirer reported.

The request came after the US Postal Service informed the key swing state that some ballots might not be delivered on time because the USPS' delivery standards couldn't accommodate the state's tight election deadlines.

Thomas J. Marshall, the general counsel and executive vice president of the USPS, sent a letter July 29 to Pennsylvania Secretary of State Kathy Boockvar warning of the issue, which could disenfranchise voters.

Boockvar's office oversees the election.

Last month, NPR reported that at least 65,000 absentee or mail-in ballots had been rejected in US primary elections this year for arriving past the deadline. In most cases, the tardiness was not the fault of the voter.

In Pennsylvania, a little over 1% of the 1,460,700 primary mail-in-ballots were rejected.

That could be a problem in a close race this November, especially in a swing state. According to results posted by The New York Times, Donald Trump won the state over Hillary Clinton in 2016 by 44,292 votes.

If the court approves Pennsylvania's request, it could mean the result of the presidential election will not be known until days after November 3.

Trump has long attacked the USPS, and on Thursday he said he planned to oppose increased funding for the department specifically to hurt its ability to handle increased mail-in voting. The president has claimed mail-in voting benefits Democrats, an idea challenged by experts, and has also claimed with no evidence that it could lead to widespread fraud.

"They want $25 billion — billion — for the post office. Now they need that money in order to have the post office work so it can take all of these millions and millions of ballots," Trump said in an interview with Fox Business on Thursday morning. "Now, in the meantime, they aren't getting there. By the way, those are just two items. But if they don't get those two items, that means you can't have universal mail-in voting ... because they're not equipped."

Business Insider previously reported that despite claims made by Trump, fraud by mail-in ballots is almost nonexistent, and there's been no evidence that the practice benefits or harms any political party.