Washington, DC (LifeNews.com) -- Rudy Giuliani is continuing to slide in the polls as he is plagued by more criticism over his position on abortion. The former New York City mayor has drawn strong opposition because of his pro-abortion views, but recent flaps about supporting taxpayer funding for abortions and donations to Planned Parenthood haven't helped.

A new CNN poll shows Giuliani has dropped a large nine percentage points from March to May -- going from 34 percent nationally to just 23 percent.

Virtually every other candidate has gained or stayed the same in the poll and benefited from the ex-mayor's slide.

John McCain, who has been emphasizing his opposition to abortion recently and said Giuliani would have problems attracting GOP voters over abortion, rose from 18 to 23 percent from March to May.

Fred Thompson, the pro-life former Tennessee senator who is not officially in the race, rose to 13 percent from 11 percent in CNN's April poll.

Mitt Romney increased a point to 10 percent, New Gingrich, who is not running, rose from 8 to 9 percent, and Mike Huckabee, the pro-life former Arkansas governor, moved to 3 percent from 1 percent.

Sam Brownback and Tom Tancredo also rose 1 point to 2 percent each while other candidates just registered the support of one percent in the survey.

CNN conducted telephone interviews with 414 registered Republicans from May 4 to May 6 and the margin of error is 5 percent.