The bitter dispute about North Carolina’s elections laws returned to a federal courtroom here on Monday as the state’s voter identification requirement went on trial. The week’s proceedings will affect election practices in North Carolina, a state that has been closely contested in recent years and where voting rules could play a part in deciding tight elections, from local races to the 15 electoral votes for president. Court rulings here could also provide an early glimpse at how the federal courts might examine balloting laws in the wake of the United States Supreme Court decision that, in 2013, upended a significant component of the Voting Rights Act. “The North Carolina litigation is the leading litigation in the post-Shelby world,” said Edward B. Foley, an elections law expert at Ohio State University, referring to the Supreme Court’s decision in Shelby County, Alabama, v. Holder. “It’s the test case, the battleground case more than any other.” The trial about North Carolina’s identification standard, which requires voters to produce one of six accepted credentials or to submit a provisional ballot, is included in a broader challenge of the election law changes that the state’s Republican-dominated legislature first approved in 2013. Then, as now, supporters of the alterations to voting procedures described them as safeguards against potential fraud, but critics condemned them as thinly veiled efforts to throw up barriers, particularly to black and Hispanic voters.