Is there a clear constitutional right to vote in the United States? The answer, traditionally, has been no. That’s what Republican-dominated states were banking on when they moved, after the 2010 elections, to restrict the franchise. But their campaign has seen a legal backlash against those efforts—one that may end up establishing that there is a right to vote in the U.S. after all.

Many people are surprised that the Constitution contains no affirmative statement of a right to vote. Several amendments phrase the right in a negative way: the right to vote shall not be denied “on account of race” (fifteenth amendment), “on account of sex” (nineteenth), or, as long as you’re eighteen, “on account of age” (twenty-sixth, which lowered the voting age from twenty-one). But within those broad strictures, the Constitution has long been read as leaving up to the states how to register voters, conduct elections, and count the votes.

After the electoral landslides of 2010, the new Republican administrations in eleven states took advantage of this broad latitude to enact laws that limited the right to vote. (Jane Mayer wrote about these laws in the current issue of The New Yorker.) Many of these laws purported to address the problem of voter fraud (which may not in fact exist) by imposing photo-I.D. requirements at the polls. At the time, these laws seemed to be on solid legal ground. The Supreme Court, in an opinion by liberal hero John Paul Stevens, had given its imprimatur to an Indiana photo-I.D. law in 2008. According to Stevens, the law served Indiana’s “interest in protecting the integrity and reliability of the electoral process.” In light of Stevens’s opinion, it seemed like the states had carte blanche to change their laws.

But as it turned out, they didn’t. The Justice Department, liberal public-interest groups and, on one particular occasion, the Obama campaign, have filed a series of challenges to the new law over the past few months, and they have met with remarkable success. The Justice Department blocked the implementation of newly restrictive voting laws in Florida and South Carolina. Wisconsin and Texas laws have also been halted. After a dramatic series of hearings, local courts stopped the implementation of the Pennsylvania law requiring new forms of voter identification. As in several of the others states, the Pennsylvania ruling only delays implementation of the new law until after the 2012 election, leaving them in place for subsequent ones, but of course next week’s election is the immediate issue on the table.

The most revealing fight took place in Ohio. Just as the state is the most important political battleground of the year, it is the center of the legal controversy over voting. It was the one place where the Obama campaign felt compelled to file a lawsuit of its own. The Ohio secretary of state, a Republican, had cut off early voting, on the weekend before the election, for all voters except members of the military. The campaign sued on behalf of “Democratic voters who may not be able to vote if the right to vote early in person in the three days prior to Election Day is taken away.”

It was, in many ways, a novel claim. After all, many states allow no early voting at all. What was wrong with Ohio limiting early voting to some times, but not others? (The secretary did not end all early voting.) If there were no constitutional right to vote, what was wrong with Ohio managing its polling practices as it saw fit? But Federal District judge Peter C. Economus agreed with the Obama campaign and overruled the change in the polling times. While there may not be a constitutional right to vote, the judge noted, “the United States Supreme Court has reiterated time and again the particular importance of treating voters equally.”

In other words, once a state sets up rules, those rules have to treat everyone the same way. By giving some voters, but not others, the right to cast ballots on the weekend before the election, the state was acting unconstitutionally. “The State may not, by later arbitrary and disparate treatment, value one person’s vote over that of another,” he wrote, “Here, that is precisely what the State has done.” Earlier this month, the Sixth Circuit affirmed Economus’s ruling.

The message of the rulings in the Ohio case is that the courts will not sit by idly as partisan state legislatures rewrite the voting rules to help their parties. As the Sixth Circuit noted, “Partisan state legislatures could give extra early voting time to groups that traditionally support the party in power and impose corresponding burdens on the other party’s core constituents.” That, of course, was what happened in Ohio. A Republican secretary of state changed the rules to help military voters (presumably more Republican) and limit the rights of others (older, poorer, and thus presumably more Democratic).

This judicial backlash against Republican overreaching may recede after the 2012 election—or it may establish an important new constitutional right. (The Supreme Court declined to hear an appeal of the Ohio case before the election, and has not yet intervened in the current election.) In any case, even with action by the high court, the law looks different today than it did at the beginning of the 2012 campaign. The courts, by ensuring an equal playing field, have done their job.

Illustration by Maximilian Bode