>Of course I want an informed electorate, but...slippery slope...
Well conceivably there could be a slippery slope in restricting the franchise. There's a definitely-real slippery slope in expanding it though.
The expansion of the franchise is an entropic process, like your car's engine performing worse at 150,000 miles than at 15,000. It is not the only such process affecting governments, but neither is it the least important. Out-of-control expansion of the franchise in a democracy, historically and in classical theory, results in the cessation of said democracy. I believe that the present state of the US is evidence of this proposition, but we don't need to belabor the point.
Do you think that American democracy functioned poorly before, say, the ratification of the 19th Amendment? If the franchise was restored to the state of, say, 1890 modulo a few allowances for the descendants of slaves, do you think the quality of American government would be better, or worse than today? I believe it would be better, although you could certainly identify particular individuals and organizations who would be worse off. But that's just like, my opinion.
If you share the typical modern concerns about the plight of the Negro, I would note that the American Republic c. 1860 fought and won a catastrophically bloody and destructive war over the issue. Would the America of 1960, or 2018, have done the same?
>all nonviolent criminals ought to have the right to vote
I didn't mention anything about nonviolent criminals. Should serial rapists have the right to vote? A man sent down the river for a few decades for murder or somesuch, he's free in his mid-40s, should he be allowed to vote? He's paid his debt to society, after all. If he didn't vote, perhaps he'd feel alienated and kill someone again. If your answer is "no", aren't you worried about a slipper slope? You start disenfranchising murderers, next thing you know you're preventing robbers and Congressmen from voting.
>Voter ID laws are dumb, they are said to be put in place to prevent people from voting twice but that's such a trivial issue, especially considering that most people don't vote anyways, voting sucks, who the fuck is going to stand in line TWICE and be at the polls all day to make no difference in the election whatsoever.
Well, which is it? Is voting no big deal that doesn't make any difference, or is it something so important that every single breathing human being within the borders of the United States has a paramount positive right to do it? Is it purely symbolic? If so, what are you worried about? If not, what's wrong with the same level of quality control that 7-11 uses to sell Natty Light?