Its clear now that the US Presidential election is going to depend on some very close results in a number of key states.
In Nevada, Wisconsin & Michigan both candidates are within 1% margins of each other and the percentages jumping around with every new batch of votes.
If Biden wins all three he is at 270 electoral college votes and the Presidency.
Trump is currently around 10% ahead in Pennsylvania with 80% of the vote counted, but there is an expectation that this state could also become close.
Close results in key states mean recounts and Court challenges.
There was a huge increase in mail-in votes in this election and reports are that it skewed heavily toward Biden.
The Democrats encouraged it because of COVID fears.
This is why Trump had huge margins in these close states on Election night that have been eroded as time has gone on.
But mail-in votes are inherently less reliable, more prone to human error and more open to challenge than in-person votes.
Obviously it is difficult to fake a human being walking into a polling station, showing ID and voting.
Its also less prone to human error. Press the button or pull the lever for your candidate - how hard can that be?
But mail in votes require matching signatures, valid post dates, witnessing, properly marked ballot papers etc.
There are a lot of requirements to try to ensure the integrity of the vote.
The Trump lawyers will be pushing the Courts to strictly ensure that every requirement is properly met on every single mail-in ballot.
And they will probably win this point, because if the legally required security requirements aren't met then its not a legally valid vote and the integrity of the electoral process is compromised. The newly 6-3 conservative Supreme Court will likely rule in Trump's favour on this.
Trump has spoken about fraud, and there is always some fraud in elections.
But there is a far more significant issue with mail-in voting - human error.
If just 0.5% of mail-in voters made some sort of mistake in the numerous requirements they needed to fulfil then these votes will be invalidated and these key close states will be won by President Trump.
Humans make mistakes.
The more requirements, the more chance of mistakes.
Biden may regret encouraging mail-in voting when he realises that is going to lead to Courts and re-counts invalidating crucial votes that may decide the Presidency for Trump.
Certainly this is going to be fought out over many weeks if not months before we have final results.