ALBANY – The chairman of the state’s politically powerful Conservative Party yesterday warned Republican officials that they would weaken their own party and strengthen his if they choose to back candidates in statewide elections next year who do not actively seek Conservative endorsement. The statements by Michael Long come amid increasing signs that Republican officials and the front-running candidates in next year’s highest-profile races are ambivalent about Conservative Party support.

The district attorney of Westchester County, Jeanine Pirro, has not spoken to Mr. Long since before announcing more than two weeks ago that she plans to challenge Senator Clinton’s re-election bid next year. And while he was governor of Massachusetts, William Weld, who hopes to be the 2006 Republican nominee for New York governor, supported abortion rights and same-sex marriage – two positions that are anathema to Mr. Long.

“If they make the decision to go it alone, that’s fine,” Mr. Long said. “I don’t know what people are thinking. But I think we need each other. We are a minority party, and some people would call us a splinter party. But I would remind you that splinters do hurt.”

Republicans and Conservatives famously parted ways in 1990, when the Conservative nominee for governor, Herbert London, nearly outpolled the Republican nominee, Pierre Rinfret. Party leaders vowed after that to remain close, putting together a coalition ticket in 1994 that resulted in Governor Pataki’s surprise upset of Mario Cuomo and the takeover of the attorney general’s office by another Republican, Dennis Vacco.

Mr. Long said he has largely been left out of high-level Republican discussions over next year’s candidates. He is said to have privately assured Republican officials of his support for Mrs. Pirro as a candidate for attorney general, for instance, only to be shocked at hearing that the veteran prosecutor planned to challenge Mrs. Clinton instead.

The chairman of the Republican State Committee, Stephen Minarik, insisted he continues to view Conservative Party support as essential. And he predicted that if Mrs. Pirro and Mr. Weld win the Republican endorsement, they will win the Conservative Party endorsement too. He said that he and Mr. Long speak frequently and that relations between their parties haven’t cooled. Still, Mr. Long, who said he plans to meet with Mr. Weld soon for a discussion of the issues, did not rule out the possibility that the Conservative Party will run its own candidate for U.S. Senate or governor, or both.