Reuters:

A special election on Tuesday for an Iowa State Senate seat could change the balance of power there and encourage Republicans to try to overturn the state's approval of same sex marriage.

... The National Organization for Marriage started sending mailers into the district in October.

The political director of The Family Leader, an Iowa-based group that has been a leading opponent of same-sex marriage, issued an email plea to supporters five days before the election, saying Golding was a "conservative Christian who shares our views on life and marriage."

A Golding win on Tuesday would open "a huge opportunity for conservative, pro-family legislation" to pass the state senate, the email said.

One Iowa, a group which supports same-sex marriage, has been soliciting campaign donations on its website, urging supporters to "help protect marriage equality in Iowa."