How does the right thing at the right time turn into the wrong thing 40 years later?

Let us look closely, and see: Claiming the Voting Rights Act of 1965 was designed eventually to make its presence redundant, the Supreme Court ruled last week that a key section of it deserved a reworking, partly because a special provision, which once did much good, is today having a negative impact on the people and parties involved.

The original Voting Rights Act, described by all as an elegant project, focused completely on ballot access, but found this wasn't enough. As Abigail Thernstrom wrote in 2009 in the National Interest, white Southerners found that "while it was nearly impossible to limit black voters' access ... it was still possible to limit the power of the votes they cast."

When a district with many black voters seemed poised to elect a black candidate, local officials would merge it with others in one at-large district, turn elective offices into appointive ones, or draw district lines to ensure white majorities -- and these doings soon drew a response.

In 1969, the Supreme Court ruled that states could and ought to draw district lines to elect a black candidate. In 1975, Congress extended the protection given to blacks to Hispanics and other "language minorities."

In 1982 the court ruled that when blacks weren't elected in large enough numbers, "intent to discriminate didn't have to be proven," but was de facto assumed to exist.

The first ruling, Thernstrom said, was correct, as the only alternative was the perpetuation of "Whites Only politics," but was designed as a short-term emergency measure. But the later rulings made it entrenched and expansive, and pre-clearance provisions prevented "regression." By the 1990s, race-coding districts appeared to be written in stone.

Also by the 1990s, it was becoming apparent that, if the ultimate goals were goodwill and inclusion, something had gone very wrong. It was bad for the country, as it increased polarization by decreasing the number of swing and/or moderate districts.

It was bad for the Democrats, for enclosing minorities in their separate districts created more safe seats for Republicans than it did for them. It encouraged people to think they only could be represented by those of their color.

And, Fernstrom said, it was bad for the blacks and other minorities elected in these so-called "safe districts," who found themselves safe but unable to move any further: "The black candidates who ran in such enclaves never acquired the skills to venture into the world of competitive politics in majority-white settings. They were ... thrust to the sidelines of American political life."

Democrats prided themselves on being the more diverse party, but they began to find in the 21st century that, while they excelled in amassing warm bodies, the Republicans had rising stars.

They had House members; the Republicans had state and national figures, and from states which the Voting Rights Act had described as bad bets: Asian Indians are governors in Louisiana and in South Carolina; Hispanics are governors in New Mexico and Nevada, and senators in Texas and Florida, and a black senator in South Carolina, who had first won Strom Thurmond's old House seat -- from one of Thurmond's sons.

Not filling a "black seat" is a boon to a promising candidate. "The best thing that ever happened to Obama," a lawyer told Thernstrom, "was [that] he ran for a heavily minority congressional district in Chicago, and lost."

Add the doctrine of unintended consequences to the good intentions that hell has often been paved with, and you have an act that is ripe for revision. And soon.