Responding to passage of a gay marriage bill in the Minnesota Senate, the coalition of groups formed to campaign against its legalization described Monday as a “sad day” for Minnesota.

The Senate followed the House in approving the legislation after a roughly 4-hour debate.

Democratic Governor Mark Dayton is scheduled to sign the bill into law during a ceremony at 5PM Tuesday on the front steps of the Capitol.

Legislative approval comes roughly two years after lawmakers approved a constitutional amendment which sought to ban gay nuptials and six months after voters rejected it.

“Today is an historic and sad day for the state of Minnesota,” Minnesota for Marriage said in a statement. “As a result of years of campaigning by gay 'marriage' activists awaiting a time when DFL leadership in the Minnesota legislature and governorship would be ready to champion their cause (contrary to the will of Minnesotans), the Minnesota Senate joined the Minnesota House of Representatives in passing the same-sex 'marriage' bill. This bill not only upends our most foundational institution of marriage, redefining it as genderless and declaring mothers and fathers as 'neutral' in Minnesota – it also fails to protect the most basic religious liberty rights of those who believe based on their faith that marriage can only be the union of one man and one woman.”

“Now we are being told that redefining marriage poses no threat to religious liberty – that 'everything will be ok' – and again, we argue that this is false. Over one million Minnesotans will be forced to either affirm what they believe to be false or subject themselves to prosecution and insult as 'bigots' and 'criminals' under our law with the passage of this bill.”

Brian Brown, president of the National Organization for Marriage (NOM), which campaigned heavily in favor of last year's referendum, said separately that the decision would end the careers of many lawmakers.

(Related: NOM's Brian Brown predicts defeat for Minnesota lawmakers who backed gay marriage.)