MINNEAPOLIS (WCCO) — With four days until Election Day, tension is high across Minnesota, especially when it comes to support for the controversial marriage amendment.

The issue quickly exploded on social media sites last night, when a Republican Senate staffer went after Republican State Rep. John Kriesel.

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Kriesel, who’s no stranger to public debates on Twitter, fired back.

The Minnesota Senate won’t say if the staffer – Bob Koss – was fired, but a spokesman said Friday that he no longer works there.

Koss started a Twitter war that included profanity, an attack on a Republican war hero, and the gay marriage amendment. It began after Koss saw the TV ad featuring Kriesel that opposed the gay marriage amendment.

“You were good enough to fight for you country, and give your life, but you’re not good enough to marry the person you love,” said Kriesel in the TV ad.

In a series of increasingly hostile tweets, Koss called fellow Republican Kriesel a “RINO” – a.k.a. Republican In Name Only.

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Kriesel responded with a profanity.

And Koss unleashed a string of hostile and profane messages, including this one: “Go ahead and play your veterans card to shreds as you’ve done. You’re a self-serving SOB and I pity you.”

Kriesel is a severely wounded Iraq war veteran who lost both his legs in a roadside bomb explosion.

As a state legislator, he bucked his party on the gay marriage amendment, one of only three Republicans to vote against it.

A spokesman for the GOP Senate issued a statement saying only that “Bob Koss is no longer an employee, or employed by, the Minnesota Senate.”

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Koss later apologized on Twitter for his remarks.