By WILL LESTER, Associated Press Writer

WASHINGTON (AP) - Hillary Rodham Clinton's popularity has slipped sharply in the last year as she prepares to make her historic bid for the U.S. Senate official - from almost 70 percent at the height of President Clinton's impeachment struggle to just over 50 percent in an Associated Press poll.

The first lady's favorable ratings soared into the high 60s at the height of the impeachment drama in the winter of 1998-99. And they were at 58 percent in a June AP poll before slipping to just over 50 percent in the new national poll conducted for the AP by ICR of Media, Pa. Her favorable rating in New York alone slipped 20 points in the last year, to below 50 percent.

Mrs. Clinton, who plans to make her Senate candidacy official on Feb. 6, now trails New York City Mayor Rudolph Giuliani, her likely Republican opponent, among New Yorkers in a head-to-head matchup in state polls _ a reversal from a year ago.

"I think many people, myself included, felt sorry for her (during the Monica Lewinsky scandal)," said Chester Suppes, a retired financial planner from Geneva, N.Y. "But when it comes down to the nitty gritty of hiring her for the Senate from New York, 'No way, Jose.' "

Now Mrs. Clinton needs to revive the favorable aura that surrounded her when she campaigned for Charles Schumer in the 1998 Senate race.

She was greeted by roaring ovations in those days, a combination of the enthusiasm of the partisan Democratic crowds and the sparkle of her celebrity. At a New York Democratic Committee Christmas party last month, a speaker's effort to get the crowd chanting "Run, Hillary Run" petered out with few others taking up the cry. But her recent appearance on David Letterman's late-night talk show got rave reviews.

The campaign trail has occasionally been bumpy for Mrs. Clinton, who received heavy criticism for her husband's pardon of imprisoned Puerto Rican nationalists and her own reluctance to immediately respond to comments by Palestinian leader Yasser Arafat's wife that were critical of Israel.

Despite her slide in the polls, Mrs. Clinton is slightly more popular than her husband, whose favorable rating was at 47 percent in the poll of 1,022 people taken Jan. 7-12. The poll's error margin is plus or minus 3 percentage points.

Three-fourths of the people in the national AP poll said they thought it was appropriate for a first lady to run for the U.S. Senate. A third thought that senator was the best way for her to be most effective in public life after the president leaves office next year, with other choices - such as a foundation head or writer/lecturer tied for second.

Marjorie George, a Brooklyn, N.Y., schoolteacher, said she wished Democrats had a stronger candidate running, but she far prefers Mrs. Clinton to Giuliani.

"He doesn't play nice with others," she said. "He's basically a bully ... my way or the highway."

A majority of New Yorkers in state polls say they have concerns about Mrs. Clinton choosing New York when she had never lived in the state prior to moving to Chappaqua, north of New York City, earlier this month.

Her popularity nationally has ebbed and flowed during the Clinton presidency, said Barbara Burrell, an Illinois survey researcher, who wrote the book "Public Opinion, the First Ladyship and Hillary Rodham Clinton."

Mrs. Clinton was quite popular when she first moved into the White House, Burrell said, but that faded under the weight of her failed attempt to implement a national health care plan and news of the Whitewater investigation. Her public image already was bouncing back in early 1998 when the Lewinsky scandal pushed her favorable rating into the high 60s.

"I think she's perceived a little more politically now," Burrell said. "Republican women have always been more supportive of her than Republican men. Now people are seeing her more politically, so those who see her favorably are getting more hard-core Democratic."

Just over half of Republicans viewed her unfavorably in the June AP poll and that number has climbed now to almost three-fourths.

The percentage of the black community who view her favorably remains high nationally - almost three-fourths - though even that number has eroded slightly since June.

Mrs. Clinton was cheered like a rock star by the largely minority students of City College when she spoke at the New York City schools' commencement last spring.

And at three New York events Monday on Martin Luther King Jr.'s birthday, the ovations were as strong as ever, with audiences clapping for minutes on end, interrupting her speeches repeatedly with cheers, and in one case, spontaneously erupting into chants of "Run Hillary, Run!"

Mrs. Clinton, obviously pleased by the adulation, smiled broadly and replied: "I think I'll do just that."