After more than two years of marginalizing and humiliating his lieutenant governor, Gov. George E. Pataki announced today he is dumping her from the Republican ticket when he runs for reelection next year.

"Your unwillingness and, in fact, outright refusal to work as part of our united team . . . has been disappointing," Pataki said in a letter sent to Lt. Gov. Elizabeth "Betsy" McCaughey Ross. "You have demonstrated through your decisions that you do not share my vision for this state."

If anything, Pataki's letter played down the political and personal chasm that has separated him from the 47-year-old former teacher at Vassar and Columbia University, whom he selected in 1994 to spice up his appeal to well-educated, upper-income women.

Since coming to office, McCaughey Ross has gone out of her way to take public positions well to the left of Pataki and the state GOP leadership, such as advocating eased restrictions on abortion. She irked Pataki during his 1996 address to the state legislature by standing behind him -- in full view of television cameras -- and stealing audience attention from her boss.

The normally voluble McCaughey Ross had no immediate comment.

As Pataki jettisoned his running mate, he learned that he was losing a potentially formidable Democratic opponent in next year's election.

Rep. Charles E. Schumer (D-N.Y.), who for months has been hinting at and raising money for a possible run for Pataki's job, announced that he will run instead against Sen. Alfonse M. D'Amato (R).

"New Yorkers need a senator who will fight against Newt Gingrich's extreme positions that hurt New Yorkers every day," said Schumer, 46, who has represented Brooklyn in Congress since 1981. Schumer said gun control and jobs will be the centerpiece issues of his campaign.

Recent polls show that Schumer might have an easier time challenging D'Amato than Pataki. The governor would crush Schumer by 49 percent to 27 percent, according to a March poll by the Marist Institute. That poll showed Pataki with a job-approval rating of 47 percent, about 11 points higher than that of his political mentor, D'Amato. The popularity of the three-term Republican senator took a dive during his chairmanship of Senate hearings on the Whitewater scandal.

"Everybody has a right to run, even Chuck Schumer," D'Amato said, according to the Associated Press.

A recent Quinnipiac Poll showed Schumer beating D'Amato, 43 percent to 36 percent. Schumer has raised about $5 million, compared to about $6.8 million for D'Amato, who leads all incumbent senators in the 1998 fund-raising sweepstakes.

Schumer's decision sets up a potentially fractious primary battle against New York City Public Advocate Mark Green, who lost to D'Amato in 1986. Former vice presidential nominee Geraldine A. Ferraro, who failed to win the Democratic nomination for Senate in 1992, has said she also might run again.

Green had hoped to raise enough money and line up enough political support to scare off all challengers and prevent a divisive nomination fight. In 1982, many analysts said that D'Amato owed his narrow reelection to a bitter Democratic primary campaign that weakened his ultimate challenger, Robert Abrams.