(CNN) - The rematch is on.
A former state lawmaker in Massachusetts who narrowly lost his Republican challenge in 2012 to unseat a Democratic congressman will officially announce his second bid for Congress on Thursday, a GOP official confirmed to CNN.
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Former state Senate Minority Leader Richard Tisei will kick off his 2014 campaign with an event in his hometown of Wakefield, Massachusetts, in the suburbs north of Boston.
Tisei is a rarity in the GOP. He's openly gay and a supporter of abortion rights and same-sex marriage. But he's also an advocate of smaller government and lower taxes.
In 2012, the 26-year veteran of the Massachusetts state legislature lost by just over 3,000 votes (out of nearly 400,000 cast) to longtime Democratic Rep. John Tierney, who at the time was battling ethics issues. Last year a congressional ethics panel decided not to investigate allegations that Tierney failed to report hundreds of thousands of dollars of his wife's income.
Last month Tisei announced he would set up an exploratory committee. If Tisei defeats the nine-term Tierney in November, he would become the first Republican to win a congressional seat in Massachusetts since 1994.
Tisei told the Boston Globe on Monday that he would highlight in his bid how much he says Massachusetts has suffered under Obamacare.
The state's sixth congressional district is located in the northeast part of the state, known as the North Shore, from Lynn north to the New Hampshire border, and is considered the state's least Democratic district.