On Wednesday, Shelby County, Ala., will ask the U.S. Supreme Court to kill the Voting Rights Act before its work is done. If the Court agrees with Shelby County, it will be a devastating backward step in this nation’s history. Fortunately, there is good reason to believe the court won’t follow Shelby County’s road.

A hundred years ago, Supreme Court Justice Oliver Wendell Holmes lamented how little courts and lawsuits could do to combat voting discrimination in the South. He said the solution for such an injury to the democratic process must come from "the legislative and political department of the government of the United States."

Later, after three civil rights laws in a row (1957, 1960 and 1964) tried the "strengthen litigation" route but failed to end voting discrimination in the South, we finally learned Holmes’s lesson and passed the Voting Rights Act of 1965 to put the voting rights campaign in the hands of the "political departments of the government of the United States."

The Voting Rights Act has proven to be an ingenious combination of sorely needed remedies. The most immediate problem — literacy tests used as subterfuges for discrimination — was dealt with by simply banning them. However, because experience had shown that when one tactic was banned it was often quickly replaced by another, the literacy test ban was backstopped by the "preclearance provision," requiring that any new voting laws or rules be shown to be nondiscriminatory before they could be put into effect. This provision, known as "Section 5," is the focus of Shelby County’s challenge.

Two other central features of the act recognized the unusual nature of these remedies. First, they were not applied across the board nationwide, but only in those areas with the worst record of discrimination. Second, they were temporary, not permanent, meaning Congress had to re-examine then periodically to insure they were still necessary.

And here’s what we know: The Voting Rights Act has been an amazing success, widely regarded as the most successful civil rights law ever. The ban on literacy tests produced quick results, opening the registration rolls to millions of new voters. And Section 5 has been exceptionally effective for the past 45 years, blocking more than 1,000 discriminatory measures from taking effect.

As required, Congress has repeatedly re-examined the law to see that it is still needed, and that the focus on the originally covered jurisdictions is still justified. Four times there has been a careful study, with extensive hearings, and each time Congress has seen progress but not enough to stop; each time the Supreme Court has unanimously upheld Congress’ action.

The most recent time was 2006, when both houses of Congress held nearly a year of hearings with hundreds of witnesses and exhibits, and again overwhelmingly decided that Section 5 is still needed. Hard to imagine in these days of partisan bickering, the bipartisan vote to extend the law was 390-33 in the House and 98-0 in the Senate. President George W. Bush signed the extension law in a Rose Garden ceremony.

Now, the Supreme Court will consider whether to honor Congress’ judgment, expressed again so recently and so decisively. The solid record on which Congress acted makes clear that the court should.

Shelby County says the law should end because times have changed since the act was passed in 1965. But the Voting Rights Act contemplated — indeed is responsible for — this progress. What was not contemplated was a law to do just half a job.

The facts presented to Congress in 2006, and shown to the lower courts in this case, are clear. Voting discrimination in the covered states and jurisdictions is still significant, even if obviously not as horrendous as in 1965; and the problem continues to be significantly worse there than in other parts of the country. The record is a reason to do more, not to give up now.

When a doctor sees a patient who has fallen ill, the doctor’s job is to cure the patient, not simply to get the patient a little less sick.

Shelby County is clearly not aware of Holmes’ lesson. It wants us to go back to time-consuming, expensive litigation; that litigation is necessary but is simply not adequate to carry the load of fighting voting discrimination. As someone who has litigated voting cases in the Deep South at all levels for more than 40 years, I know.

When the Supreme Court is asked to declare that a law of Congress violates the Constitution, the court is taking on the most awesome responsibility. That is especially true here, where the 14th and 15th amendments gave Congress special power and obligation to combat voting discrimination. The power and obligation are to eliminate voting discrimination to the extent possible, not just to get rid of some of it.

Congress carefully and categorically decided just seven years ago that Section 5 is still needed, and it is scheduled to look at the law again eight years from now. If the Supreme Court listens to Holmes, the justices will not step in prematurely to stop the act’s important work.

We all look forward to the day when voting discrimination will be a small matter, but change takes time, especially changing deep-rooted habits. And change doesn’t go faster just because we or the Supreme Court wishes it would.

Armand Derfner is a nationally renowned civil rights attorney. He has won more than a half dozen cases before the U.S. Supreme Court, and is frequently asked to testify before congressional committees about voting rights legislation, most recently during the 2006 debate to renew the Voting Rights Act.