Jeff Wilfahrt, who has become a leading activist opposing the state constitutional amendment that would limit marriage to one man and one woman, has announced that he intends to run for the Minnesota House in District 37B, a seat currently held by Kurt Bills, a Rosemount Republican.

Wilfahrt’s son,  Andrew, who was gay, was killed in 2011 while serving in the military in Afghanistan.

“Had the GOP not put forward the Marriage Amendment for the 2012 ballot, many of you would not know my name nor would you be receiving this letter,’’ Wilfahrt wrote in a an email to friends announcing his plans to run for the House.

In that letter, Wilfahrt notes that Bills, who won the seat in the Republican sweep of 2010, supports the marriage amendment.

Wilfahrt and his wife, Lori, have become outspoken advocates for gay rights since their son’s death.

But he said the amendment is not the only issue that separates him philosophically from Bills. He describes himself as pro-choice, pro-labor, anti-photo ID and says he also opposes the move by some Republicans to require all tax increases to receive super-majority support in the Legislature.