LANSING, Mich. — A criminal defense lawyer who helped win a battle to strike down Michigan’s gay marriage ban launched her candidacy for state attorney general Tuesday, pledging to protect consumers, to prosecute hate crimes and to sue to close twin oil pipelines beneath the Straits of Mackinac.

Dana Nessel, a Democrat from Plymouth, became the first candidate to enter the race to succeed Republican Bill Schuette, who vigorously defended the 2004 voter-approved ban and is expected to run for governor. She announced her campaign alongside her wife, their two children and supporters in an area of Ann Arbor where Nessel celebrated two years ago with clients Jayne Rowse and April DeBoer in the aftermath of their victory at the U.S. Supreme Court.

Dana Nessel announces her decision to run for Michigan Attorney General, Tuesday, Aug. 15, 2017, during a news conference at Braun Court in Ann Arbor, Mich. Hunter Dyke / AP

“The office of the Michigan attorney general has lost its way,” she said. “They aren’t fighting for the little guy. They aren’t fighting to protect our people against rogue bad actors hurting our most vulnerable.”

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Nessel vowed to target corporate polluters and unscrupulous debt collectors, to make civil rights enforcement a paramount initiative and to combat discrimination in housing, voting rights and lending. She promised to file suit on her first day in office to shut down Enbridge Inc.’s Line 5, which critics fear is at risk of leaking into the waterway connecting Lakes Huron and Michigan.

Democrats and Republicans will choose their attorney general nominees at conventions next summer, months before the November 2018 general election. Patrick Miles Jr., the former U.S. attorney in Grand Rapids, signaled he too will seek the Democratic nomination, saying Tuesday to “stay tuned.” State Rep. Tim Greimel, a former House Democratic leader, also is considering a bid.

Republicans who may run include House Speaker Tom Leonard and state Sen. Tonya Schuitmaker.

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Nessel, 48, owns a small law firm in Detroit and previously was an assistant prosecutor in Wayne County. She graduated from the University of Michigan and Wayne State University’s law school. In late 2015, she spearheaded a ballot drive to amend the state constitution to prohibit discrimination based on sexual orientation and gender identity, but it was never embraced by major gay rights groups.

Schuette spokeswoman Andrea Bitely said of Nessel’s criticism: “The political silly season is underway and it’s a disservice to the hardworking attorneys in our office that work every day on behalf of Michigan taxpayers. We will stay focused on defending our Constitution and working for Michigan families.”

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