President Barack Obama delivers remarks at the 71st General Assembly of the Union for Reform Judaism, Friday, Dec. 16, 2011, in National Harbor, Md. (Haraz N. Ghanbari/AP)

President Obama delivered an impassioned defense of his policy toward Israel in an appearance Friday before a conference of progressive Jews, tacitly scolding his Republican rivals for characterizing his support for the Jewish state as uncertain.

“We stand with Israel as a Jewish democratic state because we know Israel was born of values that we share,” Obama said in a speech before more than 5,000 people attending the Union for Reform Judaism’s biennial conference, billed as the largest gathering of North American Jews this year.

“America’s commitment and my commitment to Israel and Israel’s security is unshakable.”

Obama’s appearance before the group, which represents about 1.5 million Jews in North America, contrasted sharply, in tone and in substance, with the leading Republican candidates’ remarks at a forum last week sponsored by the Republican Jewish Coalition.

The Union for Reform Judaism’s membership is predominantly Democratic, the core of the 78 percent of Jews who voted for Obama in 2008.

The audience Friday heartily applauded a list of the president’s most liberal achievements, from health-care reform to equal-pay legislation to the repeal of the military’s “don’t ask, don’t tell” policy. The event, with many young people in the audience, had the feel, at times, of a campaign rally.

Heading into an election year, some Republicans believe it may be possible to chip away some of Obama’s Jewish support, particularly by attacking his Israel policy.

Obama has called Israel’s construction of Jewish settlements in the occupied West Bank “illegitimate” and has urged Israeli Prime Minister Benjamin Netanyahu, with whom he has had a rocky relationship, to begin peace talks with Palestinian leaders.

Former Massachusetts governor Mitt Romney has accused Obama of “throwing Israel under the bus,” and at the Jewish Republicans’ forum last week, he offered a similarly sharp critique. Romney also pledged to make Israel the first foreign destination of his presidency should he win the election.

But on Friday, Obama, whose opposition to the Palestinian bid for statehood at the United Nations in September placed him at odds with some of his European allies, held up his record on Israel as proof of his ardent support.

He spoke firmly in favor of a two-state solution to the Israeli-Palestinian conflict, saying that an independent Palestine alongside a secure Israel was in the long-term interest of both peoples.

Neither Romney nor other leading Republican candidates mentioned the two-state formula — endorsed for decades by U.S. administrations — in their remarks at the forum last week.

Obama said the military relationship between Israel and the United States has never been stronger.

He cited the increase in military aid for Israel that he has secured; the U.S. partnership with Israel on missile defense; American diplomatic support to combat initiatives in international forums to “delegitimize” Israel; and even the fire-fighting aircraft he deployed to Israel last year to help put out deadly brush fires in the country’s north.

“Don’t let anyone else tell a different story. We have been there, and we will continue to be there,” Obama said. “Those are the facts.”