Probability Biden is inaugurated Jan 20

Democrats might win the resulting Civil War.

I consider this quite unlikely.  the police love trump,  and he can take command of all police forces under the insurrection act.  the military love trump except for some of the top officers,  but he's been carefully shifting forces and commands to get ready,  and I have no doubt he can call on loyal forces. most importantly,  it's his supporters who own all vast numbers of guns and ammunition,  and he has many more supporters than Biden,  since in reality he won the election in a landslide,  and that was even after many of his votes had been illegally destroyed. he can easily summon millions  of armed supporters to march on the capital and they will show up. 

If neither courts nor house nor statehouses  suffice, Trump has other options.

The reality of this election is it was a massive fix by foreign governments and Biden campaign, and there is copious proof of this.

Under either the 14th amendment, or the insurrection act, trump has the right  if his voters rights are being stepped on, to call on the military and/or the militia to intervene.  the insurrection act is frequently presented by the Mockingbird media as being old, but it was amended in 2008 and was last invoked by George W. Bush and has been invoked by many other presidents.  Whether the whole military would respond,  might be open to debate, but Trump gets to cut the orders and undoubtedly he has loyal forces.  also the definition of the militia as used in this act is all able-bodied males between 17 and 45, and if Trump calls on them pointing out that they are being screwed out of the election, you can bet your bottom dollar a couple million of them will show up with assault rifles. a million  bikers for trump showed up  in DC for Labor Day weekend just in 2016.

 the biggest question about the insurrection act is whether Trump would invoke it,  but the Democrats are already drawing up hit lists and making it plain they will  subject trump and his family to lawfare  if he leaves office, which is exactly the problem that Julius Caesar had which led him to cross the Rubicon. also trump recognizes that if this blatantly stolen election stands,  there will never again be a fair election in the US.

 the only reason I'm giving this only a .5 proposed belief,  is that I doubt it'll get that far. 

Clearly numerous Republican  apparatchiks are willing to support the steal,  either because they're already so corrupt  they fear another trump presidency,  or because they fear the conspiracy, or for whatever reason. Something has kept the Republican party from exposing voter fraud before, presumably they are in on it except perhaps for the recent trump supporters.  Kemp and Ducey  are obvious examples. so if Trump can't win in the statehouses, he's unlikely to win in the house of representatives. 

Clearly numerous Republican  apparatchiks are willing to support the steal,  either because they're already so corrupt  they fear another trump presidency,  or because they fear the conspiracy, or for whatever reason.  Kemp and Ducey  are obvious examples. so if Trump can't win in the statehouses, he's unlikely to win in the house of representatives. 

Biden is inaugurated Jan 20. (Probability.)

Stock market has had a historic run under trump from the moment he was elected,  and Biden has promised to raise taxes regulations destroy the oil industry etc. etc..  seems pretty clear the financial markets aren't taking  his "election”  seriously.

  I'm going to  estimate the likelihood of this observed fact if Biden is really going to take the oath of office  is about .2, and if Trump is going to win  is .4

There are numerous court challenges. So far the  lower courts are ducking the facts of systematic fraud  and refusing to look at the evidence citing  procedural grounds.

However, the Republicans would seem to have an 5-4  majority in Supreme Court, even if you think Roberts will defect. 

 is the Supreme Court really  going to stand back,  and allow a blatantly fake election  that is against their party  without even looking at the facts?  the experience in Gore v Bush  suggests not.

 also according to various journalistic accounts, US special ops forces seized election servers in a Frankfurt  CIA data farm. If this is true, Trump will presumably release the information which shows how all the votes really went down,  and that the CIA was at least complicit, along with a lot of evidence that's already been released ( including expert witness affidavits) of  Chinese and Iranian involvement in the election fix.  is the Supreme Court going to ignore that too?

 if you are getting impatient, keep in mind that Prior to the SCOTUS decision in Bush v. Gore, every federal court and every state supreme court had ruled for Gore over Bush every time until SCOTUS. Election contests only start next week, and the key procedural aspect of Bush v. Gore was it started as an election contest.

If it goes to the house of representatives, Republicans have a 26 to 23 edge. It goes to the house if there is no clear majority, and the house votes by  states, thus the 26 to 23  majority. (PA  has an equal number of Democrats and Republicans.)

 I'm giving this a proposed belief  of .5  because Biden may have a clear majority. 

Republicans hold a majority in the legislatures of all the key states, which according to the Constitution can seat their own electors. cf: "Each State shall appoint, in such Manner as the Legislature thereof may direct”.

In an ordinary year this would never happen, but since it's obvious there was major fraud this year, it seems very likely. 

 the Pennsylvania and Arizona and Michigan legislatures have already been briefed by Trump's legal team,  and a challenge is  before the legislature in Pennsylvania.

 giving this a proposed belief of .5  because it's very unclear they will act. 

He's currently listed  as the presumptive next president by most or all of the networks.