Nobody should lose the right to vote. Even Charles Mason, Timothy McVeigh, and the Unabomber deserve the right to vote while incarcerated because they are still part of society and their opinion on who should lead is as valid as some neo nazi that hasn't been convicted of a crime yet.
I would agree, with maybe two narrow exceptions. 1) Participation in a coup or insurrection against the federal or any state government, and 2) any action with intent to fraudulently deny any other person's right to vote or have their vote counted.
Would usually be hard to prove intent on the second one, but just the threat of it would probably stop a good bit of this nonsense. If you're trying to block others from having their fair say in our democracy, then you shouldn't have a say yourself, anymore.
While that sounds good in that specific context, there are two considerations.
If the number of people convicted is small, it only serves to set a precident for removing the right that could be applied to other criteria while not really having any impact on the voting results.
Having something like that allows for it to be weaponized against political opponents and their supporters. We can already see that with removing felons right to vote, which goes along with discriminatory convictions intentionally designed to negatively impact minorities.
Revoke their citizenship. Drop them down to documented aliens. Let them earn their citizenship back the same way immigrants do, after a probationary period, of course. And in addition to prison time.
Can imprisoned persons legally naturalize anyway? Normally they would just get deported.
I upvote for your belief in universal rights, but it's not hard to coerce people who aren't free, under some influence or aren't in their right mind. My country had voting posts on military bases, in prisons and in asylums. They also had encouragement or even boss-checks-if-you-voted campaigns in many goverment's institutions. That's a big number, especially if regular voters won't put their ballots in.
You can guess what country it ended up being. Zat iZ Very eaZy.
That is important to keep in mind to make aure their rights arent stepped on.
The chance of that happening is not an argument against the guarantee that they cannot vote who they want when they lose the right altogether. Hell, one of the arguments against women getting the right to vote in the US was that they would be forced to vote in step with their husband, which of course ignored all the single women on top of just being a reason to make it easier to vote anonymously.
Holding the government accountable is far more likely to be successful with a positive outcome than private individual stuff like pollwatchers who exist to undermine the system.
If a group wants to improve things, they should be supporting the efforts of election officials to have fair elections.