Just days before Pennsylvania’s primary election, key ground rules are being challenged in four cases now pending before state courts.

In the last week alone, Montgomery and Bucks Counties have asked their local courts to extend mail ballot deadlines in their counties; a group of voters in Southeastern Pennsylvania asked the Pennsylvania Supreme Court to give voters statewide an extra week to return ballots; and Democrats appealed to the state Supreme Court for a one-week extension and to allow third parties such as friends, family, or political activists to collect and turn in mail ballots.

The legal challenges have so far been unsuccessful but remained live Friday afternoon. The courts could scramble the election rules just days before people are set to cast their votes on or by Tuesday.

State law requires that ballots be received by county elections officials by 8 p.m. on an election day; postmarks don’t count. County officials warn that thousands of voters will receive their ballots too late to return them in time.

But Republicans opposing the lawsuits have said changes would invite voter fraud.

In one suit, funded by Democratic super PAC Priorities USA, Democrats argue the disruption caused by the coronavirus pandemic requires a relaxation of election laws to make mail voting easier.

They want the state to count ballots postmarked by primary day, provided they arrive within seven days. With some counties struggling to respond to ballot requests, extending the deadline would give voters more time to use mail ballots.

The Priorities USA suit also asks the court to order the state to permit third parties to collect ballots on behalf of voters, a technique Democrats say will help people who can’t easily access postal services or polling places, many of which are slated to be closed. And they want the state to issue uniform standards for rejecting questionable ballots.

Commonwealth Court ruled this week that it did not have jurisdiction over the issue, but Democrats appealed that finding to the state Supreme Court.

“While we are disappointed in the Commonwealth Court’s decision, we remain confident that we will prevail in ensuring equal access to the ballot to the citizens of Pennsylvania,” Priorities USA chairman Guy Cecil said in a statement.

Republican National Committee Chairwoman Ronna McDaniel tweeted Thursday that Democrats are trying to “destroy safeguards like signature verification, allow ballots to be counted AFTER Election Day, & legalize ballot harvesting.”

Another case has been brought by a group of voters from Southeastern Pennsylvania, represented by the same lawyers who unsuccessfully sought to extend the mail-in deadline. When the Pennsylvania Supreme Court dismissed that earlier lawsuit, which was brought by a coalition of advocacy groups, it agreed with the Pennsylvania Department of State that the suit’s claims were too speculative.

The voters now argue that there are real signs of tangible harm as short-staffed election offices in some counties struggle to cope with a flood of mail-in ballot requests. The plaintiffs argue that voters could be disenfranchised by voting difficulties unless the court offers some relief.

The state Supreme Court on Friday sent that case to Commonwealth Court.

Locally, Montgomery County elections officials are appealing the county court’s rejection of their request for a one-week extension, and Bucks County elections officials also asked their court for a mail ballot deadline extension.