Last week was bittersweet for the cause of human dignity.

On one hand, the Supreme Court gave us reason for applause, striking down barriers against the full citizenship of gay men and lesbians. On the other, it gave us reason for dread, gutting the 1965 Voting Rights Act. The 5-4 decision was stunning and despicable, but not unexpected. The country has been moving in this direction for years.

The act is sometimes called the crown jewel of the Civil Rights Movement, but it was even more than that, the most important piece of legislation in the cause of African-American freedom since Reconstruction. And in shredding it, the court commits its gravest crime against that freedom since Plessy v. Ferguson in 1896.

That decision ratified segregation, capping a 30-year campaign by conservative Southern Democrats to overturn the results of the Civil War. Given that the Voting Rights Act now lies in tatters even as Republicans embrace Voter I.D. schemes to suppress the black vote, given that GOP star Rand Paul has questioned the constitutionality of the 1964 Civil Rights Act, one has to wonder if the results of the Civil Rights Movement do not face a similar fate.

Or, as Georgia Rep. John Lewis put it when I spoke with him Monday, “Can history repeat itself?”

Lewis was the great hero of the battle for voting rights, a then-25-year-old activist who had his skull broken by Alabama state troopers on Edmund Pettus Bridge in Selma, while leading a march against the use of poll taxes, literacy tests, morals tests, economic intimidation, clubs, guns and bombs to deny black people the ballot. The law he helped enact required states and counties with histories of voting discrimination to seek federal approval before changing their voting procedures. (Those that behaved themselves for a decade could be released from that requirement.)

The court struck down the formula the law uses to determine where discrimination lives (and therefore, which jurisdictions should be covered), saying the dates are too old to be reliable. As Chief Justice John Roberts noted in writing for the majority, the country has changed dramatically since that era. African-American electoral participation is at levels undreamt of in 1965.

And so it is. Because. The Act. Worked.

Using that success as an excuse to cripple it, noted Justice Ruth Bader Ginsburg in her dissent, is like “throwing away your umbrella in a rainstorm because you are not getting wet.” Indeed, had the nation not changed dramatically since 1965, would that not have been cited as evidence of the act’s failure? Damned if you do, damned if you don’t, then: the Voting Rights Act never had a chance.

This court, said Lewis, “plunged a dagger in the heart” of the freedom movement. Nor is it lost on him that the majority which struck down this bedrock of black freedom included a black jurist: Clarence Thomas. “The brother on the court,” said Lewis, “I think he’s lost his way.”

So what now? Lewis says we must push Congress for legislation to “put teeth back in the Voting Rights Act.” Given that this Congress is notorious for its adamantine uselessness, that seems farfetched, but Lewis insists bipartisan discussion is already underway.

Fine. Let us demand that bickering, dysfunctional body do what is needed. But let us — African-Americans and all believers in freedom — also serve notice that, whatever lawmakers do, we will not stand placidly by as history repeats and citizenship is repealed, but that we will energetically resist by every moral means.

Saying that, I hear the ghostly echo of those who, once upon a generation, marched into southern jails, singing “Ain’t gonna let nobody turn me around.” It is an ancient song of defiance that feels freshly — sadly — relevant to our times.

Leonard Pitts Jr. is a columnist for The Miami Herald. His email address is: lpitts@miamiherald.com. He will be chatting with readers every Wednesday from 1 p.m. to 2 p.m. EDT on www.MiamiHerald.com.