On the day same-sex marriage became legal in Minnesota, the main group opposing the law announced a campaign to elect a “pro-marriage majority” to the state House in 2014.

Minnesota for Marriage said it will support lawmakers who took politically difficult votes against the gay marriage bill and encourage opposition to those who voted for it.

The lead group in favor of same-sex marriage, Minnesotans United for All Families, announced in May that it would work to re-elect lawmakers who voted for the new law.

Minnesota for Marriage spokeswoman Autumn Leva said her group’s initiative is being launched with money from the National Organization for Marriage.

A statement on the organization’s website said it will spend up to $500,000 in Minnesota and $100,000 in Rhode Island, where gay marriage also became legal Thursday.

In Minnesota, the focus is on the House because its members face election in 2014, Leva said. She said Senate races will be targeted in 2016.