The National Organization for Marriage (NOM), the nation's most vociferous opponent of gay marriage, has pledged $1.5 million to fight its legalization in New York.

Gay marriage supporters with the backing of Governor Andrew Cuomo have launched an effort to make New York the sixth state to legalize the institution. On Monday, more than 1,200 people rallied at the Statehouse.

Passage in the Senate is key, but Representative Daniel O'Donnell, an openly gay Democrat from Manhattan who has successfully shepherded a gay marriage bill through the Assembly three times since 2007, decided to go first, introducing on Tuesday a gay marriage bill in the Assembly.

NOM President Brian Brown joined the fight in New York two weeks ago when he announced his backing for Sunday's anti-gay marriage rally being organized by Democratic New York Senator Ruben Diaz Sr., the Senate's most vocal opponent.

“It's become quite clear in recent days in New York that Governor Cuomo and same-sex marriage advocates are targeting a select number of Democrat state Senators, as well as some Republicans in their desperate attempt to coerce legislators to support their agenda,” Brown said.

NOM announced it would spend $500,000 on a new ad and lobbying campaign. The group also pledged $1 million toward 2012 legislative elections, funding Democrats who vote against gay marriage and opposing Republicans who don't.

“We want to be sure those courageous Democrats and Republicans who cast their vote of conscience in favor of traditional marriage will have a strong supporter if the radical gay activists come after them in their next election,” Brown said.

NOM's video ad repackages themes from previous campaigns used in Maine, Minnesota and California, that is that gay marriage negatively affects children. (The video is embedded in the right panel of this page.)