This all sounds grossly alarmist to me. You're forgetting that the three states you mention now have Democratic governors and therefore, almost the entire electoral machinery is in their hands. That's not to say we shouldn't be vigilant but this seems somewhat exaggerated as does the notion that they would be able to practise caging on a vast scale and it would pass un-noticed. As to the wider question of playing the race card I'm sure the Repugs are figuring out some way to do it but it's nitro. One misstep and it could explode in their faces and I'm sure they are conscious of that. In fact several conservative pundits have suggested they are treading very carefully, almost running scared, on the issue. Potentially it's a two edged sword, obviously it will be a factor in some southern states but otherwise it may remain dormant, we'll have to see.