Voters in 32 states may be in for a rude awakening when they arrive at the polls on Election Day 2012, in the form of an ostensibly innocent question: "May I see your ID?" You've heard it before, of course, but the query could decide the next election.

New voter identification laws have sprung up across the country, requiring registered voters to show a government-issued identification card -- a photo ID in 16 states -- in order to cast a ballot [source: NCSL]. Supporters of these new voter ID laws argue that tighter security at polling stations cuts down on voter fraud and ensures cleaner elections. But critics of voter ID laws see something far more devious: a plot to disenfranchise or at least discourage targeted segments of the American electorate.

Voter suppression -- also known as caging -- is any action or behavior intended to deter an individual or group from voting. In the history of American politics, a wide range of dirty tactics have been used by both major political parties to intimidate or disqualify voters traditionally aligned with the opposition. During the "Jim Crow" era in the southern U.S., state and county governments evaded the 15th Amendment -- prohibiting voter discrimination based on race or color -- -- by imposing a series of literacy tests, poll taxes and even thuggish "poll workers" to block African-American voters from casting a ballot. Modern methods of voter suppression are more subtle, but the intention is the same: to employ legal and illegal means to affect voter turnout in an election.

Critics of the new voter ID laws are crying foul, accusing the states of imposing a solution in search of a problem, citing Justice Department statistics that voter fraud is extremely rare: 86 convictions out of 300 million votes cast in recent elections [source: Berman]. The real reason for the rash of new voter ID laws, critics argue, is that certain Democratic-leaning voters -- African- and Hispanic-Americans, students, the elderly and the disabled -- are less likely to possess a valid government-issued ID [source:American Civil Liberties Union]. Strict voter identification laws, they say, have the intended effect of discouraging or disqualifying traditionally Democratic voters.

Supporters of the voter ID laws insist that voter fraud, particularly by third-party voter registration groups and illegal immigrants, is a serious problem. Moreover, if requiring a photo ID to vote is discriminatory, where are the cries of civil rights violations at the airport security kiosk or the liquor store [source: Tobin]? In a landmark 2008 decision, the Supreme Court sided with voter ID supporters in Indiana, citing a "valid interest" in deterring fraud and finding no significant obstacles to obtaining an ID [source: Stout].

In an era of passionately partisan politics, both parties will do everything in their power to gain a political advantage during an election. The question is, when does a savvy political tactic become an unconstitutional breach of civil rights?

In the rest of this article, we'll examine the line between dirty politics and voter suppression, and see where Congress and the Supreme Court have weighed in. Let's start with a look at the ugly history of voter suppression in the U.S.