Rudy Giuliani, the Republican former mayor of New York, and John Edwards, the Democratic former North Carolina senator,  both dropped out of the U.S. presidential race this week.

Giuliani, who finished third in Florida’s Republican primary, endorsed John McCain, Arizona’s senator, in his battle for the nomination.

“John McCain is the most qualified candidate to be the next commander-in-chief of the United States,” Giuliani said in California on Wednesday.

Obama also charged that he was the target of an online mudslinging campaign aimed at portraying him as a Muslim, particularly in the eyes of the Jewish community.  He stressed that he was no Muslim, but rather, a Christian.

Giuliani decided to abandon the race after a dismal performance in Florida’s primary, a contest on which he had staked his campaign.

Giuliani’s withdrawal leaves McCain facing a strong challenge from Mitt Romney, the former Massachusetts governor.

Mike Huckabee, the former Arkansas governor, is still formally in the Republican race, but his lack of campaign money and limited appeal beyond Christian conservatives has left him trailing far behind.

Giuliani made his announcement before a Republican debate at the Ronald Reagan Presidential Library in Simi Valley, California, on Wednesday night.

In a further boost for McCain, rival Romney signaled on Wednesday that he was not ready to commit to a costly campaign in the states holding primaries and caucuses next week.

Several officials said Romney’s campaign was not attempting to buy television advertising time in any of the nearly two-dozen states holding elections on February 5, known as “Super Tuesday.”

Instead, the former Massachusetts governor’s current plans call for campaigning in several primary states, including California.

But he has his work cut out in the state where the governor, Arnold Schwarzenegger, looks very likely to endorse McCain.

Senior aides said on Wednesday that the governor will make his endorsement official on Thursday.

Steve Schmidt, a senior McCain adviser who managed Schwarzenegger’s campaign to be governor in 2006, called the former film actor an “exceptional governor” on Wednesday.

“We are honored that he has decided to endorse Senator McCain, and look forward to the event tomorrow,” he said.

Also on Wednesday, Edwards traveled to New Orleans, where he launched his campaign more than a year ago, to make the surprise announcement that he was ending his campaign.

“It is time for me to step aside so that history can blaze its path,” said Edwards, speaking in an area devastated by Hurricane Katrina in 2005.

Edwards had not won a single primary or caucus and had consistently polled third behind Democratic rivals Hillary Clinton and Barack Obama.

Reacting to the news, Obama praised Edwards on Wednesday for spending a “lifetime fighting to give voice to the voiceless and hope to the struggling, even when it wasn’t popular to do.”

Clinton told NBC that it was crucial to remember the “very important” contribution Edwards made “to encourage us to focus on poverty.”

Edwards did not indicate whether he would endorse either Obama or Clinton for the nomination. Such a seal of approval could boost either one’s campaign.

Edwards made the decision to run for the nomination despite his wife’s cancer recurring last year.

A former trial lawyer, he focused on U.S. poverty.

He ran for the Democratic presidential nomination in 2004 and after losing was picked by John Kerry as his prospective vice-president in that year’s White House race which Kerry lost to George Bush.

Meanwhile, Senator Barack Obama presented his views on Israel and the Middle East Monday in a phone conversation with Israeli and Jewish journalists.

As he reaffirmed his commitment to Israel, Obama spoke about his visit to the Yad Vashem Holocaust Museum: “This is something that was brought home to me during my visit to Israel, when I went to Yad Vashem in Jerusalem, the power of the names, to see each name and the life it represents, to be overwhelmed by the sheer magnitude of it I think spoke, not only to our strategic interests in Israel but also our deep moral commitments there.”

Referring to his discussions with the Jewish community, Obama said: “I’m reminded of not just Israel’s long standing role as a democracy in the Middle East and the friendship between our governments but also the way in which the Jewish people have been able to transform themselves post WWII and the State of Israel’s incredible resolve to face down the constant threats that it’s faced.”

Obama declared that he objects to a Palestinian right of return into Israel and to negotiations with the Islamic group Hamas as long as it clings to its current stance, which rejects Israel’s right to exist. He added that he will make sure to guarantee Israel’s security should he be elected president.

“I’ve also repeatedly made clear that I’m committed to ensuring that Israel remains a Jewish state and that’s why I’ve pledged my personal leadership in a process to establish two states living side by side in peace and security,” he said.

Turning his attention to the Jerusalem question, Obama said that the contentious issue will be settled through talks between Israel and the Palestinians. However, Obama also noted that he supported dialogue with Iran, while charging that President Bush’s Iran policy has failed.

The presidential candidate warmly spoke about his visit to Israel and conversations with Israelis under rocket attacks.

“When I visited Israel, we met victims of constant rocket fire into civilian neighborhoods; it drove home for me the vulnerability of so many Israeli residents and stiffened my resolve to ensure that Qassam rockets will not be fired, whether from the north or the south. No country which takes its obligation to protect its citizens would tolerate such attacks and certainly the United States would no,” he said.

Obama also charged that he was the target of an online mudslinging campaign aimed at portraying him as a Muslim, particularly in the eyes of the Jewish community. He stressed that he was no Muslim, but rather, a Christian.

“I never practiced Islam. I was raised by my secular mother,” Obama said. “I have been a member of the Christian religion and an active member of a church. I was sworn in with my hand on my family Bible.”

Leaders of U.S. Jewish organizations issued a joint letter slamming email distributed recently in English and Hebrew depicting Obama as Muslim pretending to be a Christian and working for al-Qaeda.

Clinton is known to be a favorite among Jewish voters.

Obama easily won South Carolina’s Democratic presidential primary Saturday with the help of heavy black support, dealing a setback to rival Hillary Clinton after a week of political brawling.