The ghost of segregation returns to haunt the ballot box

Out of America: Nearly 50 years after the Voting Rights Act, the Supreme Court may be about to eviscerate it

Moves to tighten voting laws are politically motivated (Getty Images)

Bloody Sundays change history. The one in Russia in January 1905, when the tsar's guards shot into a crowd of supplicants, paved the way for the Bolshevik revolution. The one in Derry, when British troops fired on peaceful marchers on another January Sunday 67 years later, lent deadly new venom to the Irish troubles. Then there's America's own Bloody Sunday, of 7 March 1965.

Once again the forces of authority, in the shape of Alabama state troopers, used violence to turn back a few hundred unarmed marchers outside the town of Selma, as they sought no more than their most elementary democratic right. The outrage led directly to perhaps the crowning achievement of the entire US civil rights movement: the 1965 Voting Rights Act that outlawed the practices used to deny blacks the vote.

Now a vital part of the measure is at risk. On Wednesday, the Supreme Court hears oral arguments in the most important case of its legal year – one that challenges the Act's "pre-clearance" requirement, whereby 16 states, either wholly or in part, predominantly but not exclusively in the Deep South, must secure approval from the Justice Department in Washington before enacting any changes to their voting laws.

On the court's docket, it's referred to simply as Shelby vs Holder, case number 12-96. The petitioner is Shelby County, Alabama, predominantly white and one of these so-called "covered jurisdictions". It argues not only that the law unfairly discriminates against it, but that in any case "pre-clearance" is no longer needed, given the end of racial segregation. The "respondent" – most of us would say defendant – is Eric Holder, United States Attorney General and head of the Justice Department, the source of Shelby County's grief.

In a way, the mere fact that the court has agreed to take the case supports Shelby's claim: the South has indeed vastly changed over the half-century since the Voting Rights Act was passed. Blacks are not threatened for seeking to vote, and electoral turnout across the South is in line with the national average. But from another perspective, the challenge is occasion not for national self-congratulation, but for the deepest concern – that a fiercely conservative Supreme Court will strike down the heart of a law protecting one minority just when that law is needed once more, to counter new forms of vote suppression against other minorities.

This time the threat is no longer confined to the South and to blacks. The 2012 election took place against a backdrop of state legislation aimed at tightening voting laws. Some made it to the statute book; others did not. The methods included stricter ID requirements, sometimes forcing people to show proof of citizenship before voting, curbs on early voting and a clamp-down on election day registration. Ostensibly, they were to counter voting fraud. But study after study has shown that this is a solution in search of a problem; in the past decade, cases of proven voter fraud can be counted on the fingers of two hands.

Beyond reasonable argument, the steps were motivated by politics. In virtually every instance, the states were Republican-controlled, and the measures would have borne down hardest on people without driving licences or passports, and those of lesser means who found it harder to get to polling stations. People, in short, who were more likely to be blacks and Hispanics, the elderly and infirm – in other words, Democrats.

In one notorious instance last summer, a prominent Republican openly admitted as much, when Mike Turzai, majority leader in Pennsylvania's legislature, told a party gathering that a new voter ID law "is going to allow Governor [Mitt] Romney to win the state of Pennsylvania". In the event, the law was blocked by a judge, and Romney failed to win either the state or the White House. The real point, however, is that Pennsylvania is a long way from the Deep South. And it wasn't just Pennsylvania. New Hampshire, Indiana, Wisconsin and Kansas were other non-Southern states with Republican legislatures that attempted to tighten voting laws.

When a party's in the minority and looks like staying that way, it basically has two ways of winning elections. One is to change message, and thus increase its appeal to voters. The other is to rig the system, by preventing as many as possible of the other party's supporters from voting. In recent elections, Republicans have chosen the latter course. Without any doubt, the Voting Rights Act – and judges outside the "covered jurisdictions" who took their cue from the Act – prevented many citizens from being unjustly disenfranchised.

And one other thing is worth noting. At a national, if not a state level, Republicans too support the law. A condition of its passage in 1965 was that it would be regularly reaffirmed. On the last such occasion in 2006, when Republicans controlled both the White House and Congress, the legislation was renewed for another 25 years, by 390 votes to 33 in the House and without a single dissenting vote in the Senate. That, it should be said, was before the advent of a president who happens to be black, the intense dislike of whom unites a fractured party.

Today, what Congress will not undo, the Supreme Court very well may. By one scholarly review, this is the most right-of-centre court since the 1930s. In previous related cases, the five conservatives who form the majority, every one of them appointed by a Republican president, have signalled they regard the Voting Rights Act as a superannuated relic. With the 2010 Citizens United ruling, the bloc cleared the way for unlimited corporate spending in elections. Now it may be preparing to rip the heart from one of the most admirable and successful laws passed by Congress, just when it is needed more than ever.