The original complaint filed by Trump's legal team in Pennsylvania contented that nearly 700,000 votes should be tossed out because campaign representatives supposedly weren't allowed to watch them being counted, but the campaign couldn't actually prove that. There's simply no evidence that ballots were counted in secret and what little the campaign could muster mostly amounted to witness accounts from idiotic poll watchers who do not understand the process.
Since that effort was always going to fail, Trump's legal team has abandoned it and amended their lawsuit to make a much smaller claim against a completely irrelevant number of votes.
The Trump campaign isn’t making that claim on the hundreds of thousands of mail-in and absentee ballots, however. Instead, in the revised suit, it targets the practice of giving voters an opportunity to fix mail-in ballots that were going to be disqualified for a technicality. It contends some Democratic-run counties allowed voters to do that, while Republican counties did not, arguing Democratic voters were treated more favorably than Republican voters. [...]
The lawsuit charges that “Democratic-heavy counties” violated the law by identifying mail-in ballots before Election Day that had defects — such as lacking an inner “secrecy envelope” or lacking a voter’s signature on the outside envelope — so that the voter could fix it and ensure that the vote would count, called “curing.”
Republican-heavy counties “followed the law and did not provide a notice and cure process, disenfranchising many,” the lawsuit said.
The problem with Trump's new lawsuit isn't necessarily a lack of evidence, it's just that this isn't the law. It's not illegal to cure ballots. Republicans didn't "follow the law" by not curing their ballots because there is no law against it. That's not how anything works.
Even if Trump's legal team could get "cured" ballots tossed out, the difference would be insignificant and wouldn't change the outcome of Pennsylvania's election. And even if Trump's legal team were successful in Pennsylvania, Biden does not actually need the state to reach 270 electoral votes.
This is pure speculation on my part, but I don't think it's a stretch to hypothesize that Trump's legal team always knew their original strategy wouldn't work, but making an audacious claim to so many votes was the only way they could perpetuate the myth that the election was somehow stolen. They know that "cured" ballots aren't enough to make a difference so they reached for a bigger claim to continue this charade for two weeks. This has been a grift from the beginning.
The first hearing in this case will happen tomorrow and I expect it will be laughed out of the courtroom.