Whether you support or oppose, agree or disagree, favor or disfavor the proposed plan to enshrine the definition of marriage as a union between a man and woman into the state constitution you must find that the news that Sen. Amy Koch had an affair quite disconcerting.

After all, as Senate majority leader, Koch was among the leaders who last year decided that, instead of passing bills related to jobs and the economy, they would put a referendum on the November 2012 ballot asking voters to outlaw same-sex marriage through the constitution, even though a Minnesota statute already outlaws it. In other words, make it illegal in a way that the courts won’t overturn the law, like what happened in Iowa.

Koch resigned her post last week amid accusations of an affair with a staff member directly under her supervision. She is married and has one child.

On Wednesday, she admitted she had the affair and apologized.

The turn of events prompted all Minnesotans, left, center and right, to think thus: If a politician is going to stand before us and tout the sanctity of marriage, then they ought to live by their own words and abide by their own marriage vows.

What a disgrace she is to Minnesota. This news has crossed the country and done more to harm the institution of marriage than strengthen it.

And it reveals the true motive for placing the proposal on the ballot: Koch and her colleagues wanted the voting public to be fiercely debating a social issue leading up to the Nov. 6 election rather than worrying about their own pocketbooks.

Nevertheless, we’re fairly sure voters will keep jobs as the leading issue that day.