I think only a small part is voter suppression, although that can be significant in close elections. I think mostly we see effects of apathy and/or despair.
I don't have stats handy, but hispanics in Texas vote at pathetic levels. (Ironic that the justification for photo ID there is stopping illegal hispanics from voting, when the citizen hispanics aren't voting. I hardly think illegals are inclined to risk felonies and deportation.) Why would this be? I think in that right-wing environment, hispanics think voting doesn't matter.
Rick Perry and Texas Repubicans are *desperate* to block medicaid expansion to their state because they don't want poor people to see that government can actually work for their interests, and therefore voting matters.