WASHINGTON — Reversing the anti-American stance of his many predecessors as president of France, Nicolas Sarkozy heralded a new and optimistic era of American-French relations yesterday on his first state visit here.

France is ready to defend the existence of Israel, Mr. Sarkozy said, but the existence of a Palestinian Arab “nation state” is essential to end Jewish state’s differences with the Palestinians. And while he said Iran should never be allowed to have nuclear weapons, he said he thought both Iran and Syria should be granted a nuclear energy capacity.

Mr. Sarkozy shrugged off France’s reputation for anti-Semitism, declaring his full support for the security and integrity of the state of Israel, which, he said, should be guaranteed by international agreement.

He recalled being aghast at hearing a Gaullist minister and close colleague in President Chirac’s government — “whom I might be tempted to name” — dismissing anti-Semitic violence in France with the remark, “Yes, there are synagogues burning, but there are also cars burning.”

Mr. Sarkozy told of his efforts, while interior minister, to confront the poison of racial hatred, only to discover that anti-Semitic attacks were not even recorded by his department, which was responsible for law and order.

“If we want to fight anti-Semitism, the first thing is to refuse to play it down,” he said. “Racism, anti-Semitism, these are such hateful beasts that the first reaction of a democratic society is to deny it, to say it doesn’t exist. But unless you agree on the diagnosis, then you cannot find the remedies to fight the source of the problem.

“When you try to explain the inexplicable, then you are about to forgive the unforgivable. There are explanations for rape; there are explanations for bank robbery. Anti-Semitism should be attacked head on.”

Talking to members of the American Jewish Committee, which yesterday awarded him its Light Unto the Nations Award, Mr. Sarkozy denied that the French were intrinsically anti-Semitic. “France isn’t an anti-Semitic country, but there is such a thing as anti-Semitism there. I want to acknowledge the fact,” he said. “Once you have recognized and acknowledged the condition, you can take it on.”

He pledged that France would guarantee the existence of the state of Israel, which he described as “a miracle.” “Look at the history of the world,” he said. The state of Israel “took millennia to arrive.”

“It isn’t because I am Jewish,” he said. “By defending the Jews, you are defending everyone in a minority.” He described the Holocaust as “this period marred by barbarism, when the 20th century returned to the Middle Ages.”

“The issue of Israel’s security is very close to my heart,” Mr. Sarkozy said. “I do not always agree with Israel’s government, but their security is non-negotiable. But I also wish a viable Palestinian state. Rather than two states, you should have two nation states. That may seem a semantic difference.”

Presumably, the French president meant that any resolution of the dispute should allow the Palestinian Arabs to have the same rights of any state, including the military resources to defend themselves. But Israel’s existence must be “inviolable,” and “the international community has a responsibility for Israel’s security,” Mr. Sarkozy said.

He said he understood that finding a resolution to the Palestinian Arab dispute was risky, but that there was no alternative but to take that risk. “The worst risk you could take would be not to have an agreement at all,” he said.

On Iran, the French president reiterated his view expressed in a recent address to the U.N. General Assembly that Iran should not be allowed to develop nuclear weapons.

But he added a rider: “At the same time, I think Arab countries including Iran have a right to nuclear power.” He said allowing Arab nations nuclear power plants would throw moderate Arabs a lifeline; the alternative would be to drive them into the hands of terrorism. The key to the impasse in Iran is the “transparency” of its nuclear program, he said.

Engagement with maverick nations, rather than the ostracizing of their leaders, has proved effective in returning Libya and North Korea to the international fold, he said. “What I have said about Iran I have said about Syria,” he said.

Tempted by a questioner to suggest a way for American to untangle itself from the Iraq war, Mr. Sarkozy refused to be drawn. “It is obviously not up to those who do not have troops in Iraq to say how and when” American and other allied troops “should pull out,” he said.

“We want a united Iraq,” he said. “There is no interest in having an Iraq which has been pulled apart and dismembered. It must be a multi-ethnic and multi-creed country. And we want a democratic Iraq. I do not believe the solution is solely a military one, and that’s putting it mildly. I know we cannot say, ‘Pull out immediately.’ Nor can we say, ‘Never leave.’ Whatever France can do to bring about a strong, stable administration in Iraq, we will do it.”

But he would not criticize President Bush or his leadership of the war. “I would not be the head of state to come over here and say, ‘This is the way out of the quagmire,'” Mr. Sarkozy said. “The Americans know the problems that they are facing.”