Pro-tip: When you win a big court case giving you the go-ahead to suppress voter turnout for your political opponents, don’t gloat about it.

That is surely one of the lessons in the remarkable news that the U.S. Department of Justice is challenging new voting-rights laws in Texas and elsewhere even after the Supreme Court ruling that eviscerated the part of the Voting Rights Act that the feds had relied on for decades to challenge voting restrictions. What made the ruling especially galling was the celebration that followed from Republicans in states, including Texas, who immediately vowed to proceed with voting restrictions that had been challenged under the now-undermined part of the VRA.

The alacrity with which Texas, North Carolina and other states have rushed to take advantage of the ruling seriously weakened the sober conservative argument, from Chief Justice John Roberts and others, that Southern states no longer needed to be singled out for special scrutiny because they had long since left their discriminatory ways behind. And it all but invited Attorney General Eric Holder to take this new step, to announce that his department would still do everything in its power to ensure fairness at the polls.

This will of course be decried as executive overreach and an assault on checks and balances, but the case for declaring it such would be much easier to make if Texas and other states hadn’t been so gleeful in their rush to capitalize on the ruling. Texas takes the cake for the speed of its response, but North Carolina surely takes the prize for sheer brazenness: The legislation making its way through Raleigh is so extreme that it earned even a tut-tut from arch-conservative Wall Street Journal columnist Stephen Moore. The legislation will not only add a strict Voter ID requirement by the polls, but reduce early voting days from 17 to 10 (early voting has been used disproportionately by African-Americans in the state), prohibit counties from extending polling hours in extraordinary circumstances, like unusually long lines, and eliminate provisional ballots for voters who show up at the wrong precinct, among other changes. A separate bill seeks to give a tax penalty to parents whose dependent children register to vote somewhere in the state other than where the parents reside, a nifty way to discourage voting by college students.

What impact would the changes have? My colleague Nate Cohn, who has generally warned against over-reaction on voter suppression measures, ran the numbers and found that the Voter ID provision alone could swing enough votes to win the state for Republicans in a close statewide election—and that’s not accounting for the early voting cutbacks and other changes. The New York Times has declared North Carolina “first in voter suppression,” a judgment quoted approvingly by election-law expert Rick Hasen, also not one prone to overstatement.