One Democrat is mocking former Mayor Rudolph Giuliani for endorsing her GOP rival in a Nassau County district attorney’s race, pointing to a “hypocritical” nod the Republican recently gave to a Staten Island candidate.

Madeline Singas, the acting DA running to replace now-Congresswoman Kathleen Rice, blasted Mr. Giuliani for backing Kate Murray, the Town of Hempstead supervisor, because Ms. Murray has no experience as a prosecutor, unlike her. When Mr. Giuliani, a former prosecutor, endorsed Joan Illuzi, the Republican DA contender in Staten Island, he ripped her Democratic opponent for lacking any legal experience other than time spent as a trial attorney.

Mr. Giuliani had said of Michael McMahon, the former Democratic congressman from Staten Island, that it was “an insult to the people of Staten Island for the Democratic Party to put up a candidate who has never prosecuted a case, never tried a case.”

The Singas camp is hoping Nassau voters feel the same way about Ms. Murray.

“It’s laughable that Rudy Giuliani would endorse Kate Murray when just a few weeks ago, opining on the Staten Island District Attorney’s race, he said ‘I believe it is an insult to the people…to put up a candidate who has never prosecuted a case, never tried a case.’ We can only assume he finds Kate Murray’s candidacy just as insulting,” said a spokesman for Ms. Singas.

“The Singas campaign wholeheartedly encourages Nassau residents to take his advice,” he added.

A Daily News editorial this morning piled on Mr. Giuliani, calling him a “shill” for supporting Ms. Murray and Ms. Illuzi, who worked for decades as an assistant district attorney in Manhattan. “After a brief run for President eight years ago, Giuliani resides today beyond political relevance. He is reduced to offering endorsements in local races, even to peddling his reputation dishonestly,” the News wrote.

Despite the vehemence from the News and the Singas camp, Mr. Giuliani’s endorsement is not to be dismissed in either race. The tough-on-crime mayor remains overwhelmingly popular in conservative Staten Island. In Nassau County, where Republicans and moderates are relatively more abundant than neighboring New York City, Mr. Giuliani’s mayoralty is viewed fondly.

Both races are expected to be very close. Voters will head to the polls next Tuesday.

Spokespersons for Mr. Giuliani and Ms. Murray did not return requests for comment.