Democratic Governor Tom Wolf’s administration plans to appeal the ruling against mail-in voting to the state Supreme Court. (File photo)

A court in the US state of Pennsylvania has struck down a landmark state election law that had eliminated barriers to voting by mail, potentially restricting access to the ballot in the key battleground state ahead of the midterm elections.

In a 3-to-2 decision on Friday, the Commonwealth Court sided with 14 Republican lawmakers who challenged the law known as Act 77 last year, declaring it was unconstitutional.

The administration of Democratic Governor Tom Wolf immediately appealed the ruling to the state Supreme Court, triggering an automatic stay that keeps the law in place during the appeal process.

Voting rights advocates warned that another ruling in favor of a moratorium on mail-in voting in Pennsylvania would have dire consequences for democracy.

The ruling is without merit and a partisan attack on voting in Pennsylvania, tweeted Rep. Dwight Evans (D-Penn.). This must not stand and I look forward to an appeal to the Pennsylvania Supreme to correct this egregious ruling.

The decision by the panel of three Republican and two Democratic judges argued that Pennsylvania’s constitution required voters to cast their ballot in person unless they had a legitimate excuse, such as having a disability or being away from home on Election Day.

State Attorney General Josh Shapiro, a Democrat who is running for governor, said the court’s ruling is based on twisted logic and faulty reasoning, and is wrong on the law.

Shapiro said he was confident the state Supreme Court would uphold the constitutionality of the mail-in voting.

Still, the Commonwealth Court’s decision raises a question mark over Pennsylvania’s election laws as voters in the crucial swing state prepare to elect a governor and a US senator in the 2022 midterm elections.

Out of a total of 6.9 million votes cast during the 2020 presidential election, just over 2.5 million were cast by mail under the law’s expansion of mail-in voting in Pennsylvania.

During that election cycle, then-President Donald Trump continued to attack the practice as being rife with fraud, sparking a debate about its use and prompting many Republicans to launch lawsuits in their states.

Gov. Wolf’s office criticized Republicans for trying to kill the state law in the service of the big lie perpetuated by Trump, who lost Pennsylvania to President Joe Biden in 2020.

Signed into law in 2019, Act 77 permits Pennsylvanians to vote by mail or absentee ballot without providing a reason.

It also allocated $90 million in election infrastructure upgrades, created a permanent list of mail-in voters, and reduced the voter registration deadline from 30 days to 15 days before an election.