@desnol Let’s talk about legal challenges, and break them down a little.
First, let’s be clear about legal challenges that have been submitted - and legal challenges he is threatening. He can threaten as many legal challenges as he likes, but it’s likely many of these won’t happen because there are tight pursestrings in play and the campaign must may for these, and any subsequent recounts in most states. In addition, some of the legal challenges the campaign suggested early make less sense for the campaign, as they would potentially risk the votes they now desperately have to hope are there to get any hope of re-flipping states.
Pennsylvania: On November 5, the Trump campaign filed a claim that poll observers were being denied access to the ballot count in Philadelphia with a federal judge. This claim was denied, as the witness the campaign brought forward admitted he could see the ballots being counted. The judge outlined an important distinction: observers are there to observe, not audit, so don’t need to see what is on each ballot. They did succeed in getting a Pennsylvania appeals court to order special handling of ballots for which missing voter ID information is supplied between Nov. 9 and Nov. 12. This will backfire, as the Trump campaign needs those votes to be counted AND contain a large margin of Republican ballots for them to turn PA or get close enough to get a recount. This is because none of those ballots had been counted yet, due to concerns about whether they would be accepted. Other legal moves in PA include trying to exclude provisional ballots cast after voters were given defective ones (on and before Election Day); and five random suits that want counting stopped until ‘meaningful transparency’ is available. Note, this is him asking to stop the count of votes cast BEFORE the close of voting. No legal definition of this was provided, and they will be dismissed. If you’re concerned about whether ballots are being treated appropriately in PA, here is a livestream where everyone can be an observer. I’ll warn you, it’s very very boring.
In most states, ballots mailed on or before Election Day count. There is significant legislation in place to allow for this, and this became important because of the targeted underfunding of USPS that removed sufficient mail services across a lot of Democrat areas in the build up to the election. The issue you refer to is in PA, and occurred when a deadlocked U.S. Supreme Court declined to overturn the Pennsylvania Supreme Court’s decision to extend the mail-in ballot deadline. That decision allowed ballots received by Nov. 6 to be counted, and also allows non-timestamped ballots to be accepted within 3 days of Election Day. Again, doesn’t matter, as those votes haven’t been counted yet and are likely to skew democrat - this lawsuit simply cements his PA loss. However, unsure why you think is a problem for the US Supreme Court, as this is already resolved? His tweets on the matter have been blocked on Twitter because they misinform the public and may have been used to discourage people from sending in their ballots in the days before and the day of the election.
Michigan: On November 4th, Trump’s campaign filed a suit to stop counting (again, the state hadn’t started on late ballots postmarked before Election Day yet) just before urban votes were to be counted. They wanted, again, "meaningful access" for campaign poll watchers to the counting of state ballots, plus access to videotaped surveillance of ballot drop boxes installed around the state from October onwards. The Judge pointed out that vote counting had been completed, so there was no more access to be given, and a previous directive was already in place that allowed them access (this was at first not clear, as COVID restrictions in Michigan meant observers refusing to wear masks were not being admitted.) The judge threw out the request for ballot box surveillance, as there was no legal claim as to why this needed to be passed over.
The legal issue you raise about ballots being delivered isn’t true. All registered voters in some states were sent mail-in ballots, as per state policy (California, Nevada, New Jersey and Vermont). They didn’t exclude anyone. Others sent all registered voters a vote-by-mail application as a way of encouraging them to choose mail voting over heading to the polls. The only variation you see is in states like Montana, which ruled to allow counties to determine how they would run this, so counties taking COVID more seriously opted for sending out ballots, but again - to every registered voter). There is no reason for this to be looked at by the courts, and it would be a bizarre play from the Trump campaign, as that variation happened largely in Republican strongholds.
There has been one case of electoral fraud in Nevada, reported to the appropriate agencies. This was a case were a Republican registered voter attempted to submit two ballots for Trump. He was caught, thanks to Nevada’s careful cross-examination of each ballot (hence why their count is slow) and only one vote was registered. Media reporting in the US has been quite clear on these issues, unless you watched the first day of Fox coverage or people are assessing the situation from GOP twitter accounts. Sadly, many are.