Mr. Klein and three Democrats formed the IDC in January 2011 as a reaction to the Democratic Conference’s two-year stint in the majority, a period which turned Albany into a laughing stock. Mr. Klein, who served as the deputy majority leader during that chaotic period, said the Democrats’ antics and dysfunction led him to leave the conference.

He is a fiscal conservative who won reelection on Democratic, Republican, Working Party and Independence party lines this year. He has always said he is a Democrat at heart and has repeatedly insisted that the IDC works in a “bipartisan fashion.” He has worked with Republicans and Democrats on legislation and most notably sided with Republicans on property tax cap legislation. 

But Mr. Klein differs with the GOP on many major issues facing the state. He has been a leading voice on raising the state minimum wage and he recently announced his support for a hydrofracking ban. He also backs campaign finance reform and has advocated for women’s reproductive rights. 

Mr. Klein said in the press release that the coalition’s goal is to collaboration as opposed to have one party dominate the discussion.

“Legislating is a deliberative, cooperative process — not a spectator sport. Having dedicated the past two years to a serious, policy-driven agenda, this agreement delivers on the IDC’s pledge to become a permanent third conference within the State Senate and to have a major voice in all policy decisions moving forward. Having worked together over the past two years, I know that Senator Skelos is not only an effective leader, but is as committed as I am to delivering major bipartisan results for all New Yorkers,” Mr. Klein said in a press release.

A spokesman for Mr. Klein said he was not talking to reporters at all on Tuesday.

State Sen. Adriano Espaillat, who has worked with Mr. Klein on legislation in the past, released a statement urging the new coalition to use common sense next year.

Mr. Espaillat said he hoped progressive legislation like raising the minimum wage, micro-stamping guns, the New York Dream Fund and Farmworkers Bill of Rights would be brought to a vote.