Like millions of other Americans, I voted last Tuesday. I did not face long lines and there were no barriers to my entry to the polling station. Everyone was quite friendly, and it was a pleasant experience.

They were so friendly, in fact, that they even offered a service to voters, advertised by a sign on the wall: Voters, presumably those who would have difficulty walking into the polling station due to disability, could wait in their idling cars, honk their horns and have someone aid them in voting curbside.

At the time, I did not think much of this. If I'm being honest, I was at first amused by the comparison of voting to checking luggage at the airport. And there was no doubt that those using the service seemed to benefit from it. But on further thought, I began to be disturbed.

It was the juxtaposition of images that bothered me. On the one hand, you had voters driving up and honking their horns to summon someone to help them vote. On the other hand, the volunteer inside the building was telling me cheerfully that I and everyone else in my state would need a valid ID to vote come 2016.

Though I do have a valid ID, the juxtaposition nevertheless bothers me. The reason is that it belies everything that, in my opinion, has made America great. America's exceptionalism arises from its ability to incorporate waves of immigrants with different skills, cultures and experiences, and unify them into a coherent whole. This process is not immediate on entry, and it is not forced; rather, generations of immigrants and the children of immigrants have wanted to consider themselves Americans because being American accompanies the promise of a better life.

This promise is premised on the perception of mobility, social and economic mobility. The phrase "land of opportunity," so closely associated with America, is emblematic of this notion. Sure, not everyone will succeed, but the possibility of success exists.

What I saw at the polling place Tuesday was in stark opposition to this perception. The juxtaposition of images signaled the existence of privileged classes. Government will go out of its way to accommodate some people's voices, but will put up barriers to others. Importantly, these barriers are not in response to an actual problem; voter fraud — and particularly voter fraud of the type that would be thwarted by voter ID laws — is rare to nonexistent. Consequently, those on the wrong end of voter ID laws get the signal that their voices do not count, that they are not valued except insofar as they might provide useful labor for the privileged classes. The perception of social mobility dies in such a climate of political inequality. And because those most affected by voter ID laws are also low-income voters, these individuals are already experiencing the cost of greater economic inequality — increasing economic inequality is likely to decrease economic mobility as well.

The effects of a decrease in the perception of upward mobility driven by inequality in the political or economic spheres are pernicious. Without this perception, there is little incentive to buy into the American system. Factionalism will seem relatively more attractive than integration, and this will lead to contentious politics, little common ground and, at the margins, civil unrest. Events in Ferguson, Mo., are a recent example of this. Our political system will quite simply function less well, and be more prone to internal strife and potentially violence. Similarly, economic inequality is likely to lead to reduced economic growth, and so an economy that functions less well. In this way, political and economic inequality hurt everyone, not just those on the wrong end of the inequality.

Don't get me wrong; I'm all for aiding the infirm in doing their civic duty. But for the sake of our country, let's do the same for everyone.

Siegel is an associate professor of political science at Duke University.