SACRAMENTO — Former Rep. Tom Campbell on Friday used the first debate in the California Senate race to demand that his challengers not engage in a “whispering campaign” claiming he is against Israel or anti-Semitic.

Campbell and his two opponents in the Republican primary — former Hewlett-Packard Chief Executive Carly Fiorina and state Assemblyman Chuck DeVore — participated in their first debate, organized by a Sacramento radio station. Fiorina joined by telephone.

Campbell requested the debate after his opponents began questioning his support for Israel. Those questions were based on his voting record when he served in the House of Representatives, and on a campaign donor who later was revealed to have ties to a U.S.-listed terrorist organization.

The attacks on Campbell took a sharper turn after the Los Angeles Times reported that Fiorina’s campaign manager, Marty Wilson, told former California Secretary of State Bruce McPherson that Campbell was an anti-Semite.

Wilson denied he had said it, but the report spread quickly across the Internet and worked its way into news stories.

Fiorina and DeVore subsequently questioned whether Campbell was sufficiently supportive of Israel during his five terms in office.

“There’s no place for calling me an anti-Semite and then denying it,” Campbell said about a topic that dominated the first half of the hourlong debate. “That whispering campaign, that silent slander, stops today.”

Fiorina said her campaign manager assured her he did not accuse Campbell of being anti-Semitic. But, she noted, Campbell had voted to cut foreign aid to Israel, and that he was one of only 34 members of Congress who voted against Jerusalem being the undivided capital of Israel.

DeVore took a swipe at Fiorina’s campaign for making “unsubstantiated charges,” referring specifically to the anti-Semite dust-up. But he refused to back away from calling Campbell a “friend to our enemies” for associating with a University of South Florida professor who later pleaded guilty to conspiring to aid a Palestinian terrorist group.

Campbell received a $1,300 campaign contribution from Sami Al-Arian in 2000 and later wrote a letter on his behalf asking the university not to fire him.

Campbell said the contribution came as the Republican Party was reaching out to Muslims and years before the criminal charges were filed.

“I certainly wish I had done a better job of finding out who he was at the time,” Campbell said.

The assertion that Campbell does not view Israel as a friend is an important one in a primary in which evangelical Christians will help determine who will advance to the general election. The GOP nominee will face Democrat Barbara Boxer, who is seeking a fourth term.

Many Republicans strongly support Israel’s right to exist as a Jewish state. Campbell said he has never flinched from showing strong military support for Israel.

On domestic issues, the three candidates clashed mostly on taxes. Again, Fiorina and DeVore primarily attacked Campbell — the front-runner in the Republican primary, according to polls.

They questioned Campbell’s past support of tax increases at the state level. For example, Campbell endorsed Proposition 1A on California’s special election ballot last May, which would have extended a series of temporary taxes. He also called for a one-year, 32 cents-per-gallon gasoline tax.

Campbell, a former finance director for Gov. Arnold Schwarzenegger, said his support for past tax increases was aimed specifically to help California close its budget deficits. He said he does not support tax increases at the federal level.