If you want a sense of what motivates the politicans and activists who push for voter identification laws, look no further than this quote from Pennsylvania State Representative Darryl Metcalfe:
I don't believe any legitimate voter that actually wants to exercise that right and takes on the according responsiblity that goes with that right to secure their photo ID will be disenfranchised. As Mitt Romney said, 47% of the people that are living off the public dole, living off their neighbors' hard work, and we have a lot of people out there that are too lazy to get up and get out there and get the ID they need. If individuals are too lazy, the state can't fix that. [Emphasis mine]
As always, it's worth noting the extent to which the "47%" meme has penetrated the right-wing consciousness. It's why Romney immediately doubled-down on the statement; he's echoing many conservatives when he says that Obama's supporters are people who won't "take responsibility for their lives."
When it comes to Metcalf, he alludes to another view that has taken hold on the Right. Namely, that democracy requires independence from government benefits, and that self-governance is threatened when too many are "dependent" on federal aid. This isn't a fringe belief; it was echoed by anchors on Bloomberg-who worried that the 47% will somehow subvert democracy by voting their financial preferences-and has its roots in the founding of the country.
The Founders were preoccupied with something called "republican virtue." As they saw it, a democratic society required a citizenship with the ability to act with enlightened self-interest. For them, white male landowners were capable of achieving this state-Africans were subhuman, and women were governed by passions and sentiment.
It's not hard to find a version of this view in conservative rhetoric around voter identification and the welfare state. Taking benefits makes you dependent, and dependency creates a state of mind that blinds you to enlightened self-interest. Reasonable people can differ about whether there is a distinction between "reason" and "passion"-or whether there's such a thing as "enlightened self-interest"-but there's something outmoded about the idea that material motivations taint democratic action.
But this is part of what drives the thinking behind voter identification laws, and more broadly, opposition to the welfare state. It has a long history in American political thought, and while liberals may score a win over mandatory ID at the polls, the idea that some deserve to participate-and some don't-will be with us for the duration.