Will there be a third party candidate for US president that spoils the election? That is, will a third party candidate take enough votes away from a Democratic or Republican candidate, such that the one who would have otherwise won will instead lose?
For example, if the Green Party nominates Cornel West, and he takes votes away from Biden in key states, causing Trump to win, that would count. Or if Trump runs as a third party, and takes away votes from DeSantis, causing Biden to win, that would count.
This will only look at the effects of a single third party. If a Libertarian candidate and a No Labels candidate take away enough combined votes from a Republican, but neither would individually have spoiled the election, it would not count.
This will look at electoral college numbers, not just percentages of national votes. If the exact polling data is unavailable, it will instead be based on the most reliable analysis, such as by websites like FiveThirtyEight. If it is strongly disagreed about, I reserve the right to resolve to a percentage matching my credence.
@EvanDaniel Usually there are exit polls and other polling available to indicate who they would have voted for if they hadn't voted for the third party candidate. That doesn't account for them having chosen to not go out at all, but I believe it will be clear enough. For example, with the 2016 election, we can clearly say that neither the Green Party nor the Libertarian Party spoiled the election.
Hopefully the data will be available in a way where this can be calculated. If not, I'll go with reliable analyses done by political experts, like I mentioned in the description.