A federal trial in Milwaukee on Wisconsin’s 2011 voter ID law concluded recently, and the verdict, when it comes, will help define the future of the Voting Rights Act, which has been in question since the Supreme Court gutted a core provision, Section 5, in June. This case could also set an important precedent for lawsuits recently filed against similar laws in Texas and North Carolina. The Wisconsin law, which is now on hold, is among the strictest in the country. It requires a voter to show poll workers government-issued photo identification, like a driver’s license or passport. The law’s challengers, which include the A.C.L.U., the League of United Latin American Citizens, the League of Young Voters and several private citizens, sued under Section 2 of the Voting Rights Act. That section, which survived the Supreme Court’s ruling, prohibits state and local governments from imposing any “voting qualification or prerequisite to voting” that has a racially discriminatory effect. The test is whether a law causes minority voters to have “less opportunity than other members of the electorate to participate in the political process.” The plaintiffs presented substantial evidence that the Wisconsin statute had precisely that effect.