The Colorado Supreme Court has ruled that Donald Trump is not eligible to hold the office of President under the US constitution's insurrection clause:
A majority of the court holds that Trump is disqualified from holding the office of president under Section 3 of the 14th Amendment
They have ruled that he should not appear on the ballot for the Republican presidential primary on 5th March, but his team will presumably appeal this decision to the US Supreme Court.
There is speculation that if Trump is the Republican candidate for President (currently a n 85% chance - /BruceGrugett/will-donald-trump-be-the-republican), the Colorado Supreme Court ruling would stop him from appearing on the ballot in the general election.
Will he appear on the ballot?
If Donald Trump appears on the ballot as the Republican nominee, this market will resolve to YES
If Donald Trump appears on the ballot as the nominee for any other party or as an independent candidate, this market will resolve to YES
If Donald Trump does not appear on the ballot and it is not possible to vote for him (or the only way to vote for him is to write his name in), this market will resolve to NO