Ridiculous.

The argument that the 14th Amendment (which has two Ms, not 3) is self-executing, meaning that it doesn't have or need a statutory trigger, like a conviction of a crime, is pretty persuasive as a theory, and I suppose the writers of the amendment never even considered the possibility of a former president having participated in an insurrection and then running for office again. More problematically, it contains no guidance as to who decides and how; decisions about ballot access being left to individual states. So if SCOTUS upholds the Colorado case and decides it applies only to Colorado, where does that leave the other states? Presumably that decision would acknowledge that the Colorado court correctly applied the 14th Amendment in holding that it could be a basis for excluding Trump from the state's primary ballot.

But take another case, in Minnesota, in which that state's supreme court held that only a political party could decide who can be on its primary ballot and that the courts have no power to do so, but left the question open as to the general election. So presumably Minnesota has to leave him on the primary ballot if the GOP wants him there, but his appearance on the GE ballot could be contested in court. This seems to be true of some other states as well. Or, say the Colorado case is held to apply to all the other states, upholding the factual finding that there was an insurrection and he was part of it. Does this mean that he has to be excluded from all ballots nationwide, or just that the other states can choose to do so? Would this effectively federalize election processes that have always been delegated to individual states?

And what if in the future some of the same raving election-denier GOP lunatics in one or more states try to exclude a Democratic candidate from the ballot using some specious claim that he had engaged in insurrection (which could be something as innocuous as a governor vetoing a GOP bill), and they get their GOP Secretary of State to actually do it?

This case is a lot more complicated than a lot of people have made it out to be. I'm surprised it got as far as it did, and I expect the liberal justices to vote to overturn it along with the conservatives, if for different reasons.

I did think this aspect of states rights through some time ago when I looked at education. I agree that it would certainly cause some mayhem when it comes to national elections, but I intimated that a good idea takes root and it's practicality often follows quickly.
Since the Supremes seem to gravitate to congressional guidance with their decisions, could not acceptance of Colorado imply that congress has to establish a national protocol for elections.
Will their decision demand Colorado putting him on the ballot? That would be establishing a national criteria in its own right, wouldn't it?
It would seem to me the state's rights crowd could hold that trump is disqualified as trump was decided to have participated in an insurrection.
At some point, the 14th Amendment, has to exhibit some authority. Or is it a kick the political can down the road?

They would either have to disqualify him nationwide, or overturn the ruling completely.

Upholding the ruling for one state only would be a recipe for chaos.

Disqualification for federal office under the 14th should be the domain of the federal courts.

Allowing individual states to disqualify a candidate for federal office would permit 50 different, unreviewable interpretations and enforcements of the constitution.

The Supremes seem to rely on Congress, maybe this should force congress to establish a national voting structure.