A feckless PA republican controlled General Assembly (legislature) was responsible for passing PA Act 77, which allows anyone to use a mail-in-ballot.
“The PA Constitution does not restrain the legislature from designing a method of voting in which votes can be delivered by mail by qualified electors for canvassing,” Justice Christine Donohue wrote in the opinion. “The only restraint on the legislature's design of a method of voting is that it must maintain the secrecy of the vote.” That secrecy, Donohue wrote, is present in Act 77.
The blame for PA's indiscriminate use of mail-in-ballot lies with the PA republican controlled General Assembly - IMHO.
And the Republican candidate for governor in PA this year is a dope who is promising to "fix mail-in ballots" in PA ... even though HE VOTED FOR Act 77 in 2019 as a state senator.
That pretty much tells you everything you need to know about how fouled-up the political scene is in PA.