JERUSALEM -- Israeli Prime Minister Binyamin Netanyahu's national security adviser said Tuesday that the push for Palestinian statehood has weakened Israel's standing in the world, and he suggested that the outlook is bleak for U.S.-mediated negotiations in the region.

Uzi Arad, central in the crafting of Israel's stance on the Palestinians and on Iran's nuclear program, also argued that new U.N. Security Council sanctions on Iran are inadequate to thwart its nuclear progress. A preemptive military strike might eventually be necessary, he said.

Arad's comments, made to a gathering in Jerusalem of the Jewish Agency, a body that promotes Jewish immigration to Israel, illustrated the challenges President Obama faces in laying the groundwork for peace talks, as well as reassuring an increasingly impatient Israel that the United States can stop Iran from obtaining a nuclear bomb. Obama is to meet with Netanyahu in Washington on July 6.

"The creation of a Palestinian state remains the choice of many," Arad said. "But in the process, have you failed to notice that the more we lend legitimacy to a Palestinian state, the more it comes at the expense of our own?"

Arad described the Palestinians as "major actors in the delegitimization of Israel" and questioned Israel's decision to back talks on Palestinian statehood. "In trying to make peace" via the indirect U.S.-led talks, "we are embracing an adversary who is conducting a very effective battle against us internationally," he said, though he added that Israel still aspires to peace with the Palestinians and Syria.

Arad's remarks came just days after Obama's Middle East envoy, George J. Mitchell, met with Israeli and Palestinian officials to test the two sides' readiness to engage in face-to-face talks on core issues such as borders, the future of Jerusalem, security arrangements and the fate of Palestinian refugees. So far, those contacts have not produced substantive results.

Palestinian Authority President Mahmoud Abbas agreed this spring to enter into the indirect talks. Arad's comments coincided with accusations by Palestinian officials, including negotiator Saeb Erekat, that Israel is trying to "destroy" the talks by moving ahead with projects such as the creation of a park in an East Jerusalem neighborhood that would require the demolition of 22 Palestinian homes.

On Iran, Arad did not directly address the likelihood that Israel would strike militarily. But he said he believed the international community would back such a decision. "I don't see anyone who questions the legality of this or the legitimacy," Arad said. "They only discuss the efficacy, which is interesting. It suggests that people understand the problem. And they are not questioning the right."

Arad also noted what Israeli officials have perceived as a shift in U.S. policy toward Iran, citing a subtle change in rhetoric. Officials say they think Obama is now more willing to use military force.

"I read with interest observations made by American Secretary of Defense [Robert M.] Gates, in which he didn't rule out any other options," Arad said.

"I also took notice -- all of us did take notice -- that the United States [has] changed the definition of its policy on Iran, from one that said a nuclear Iran would be 'unacceptable' to one in which it said that the United States 'is determined to prevent Iran from becoming nuclear.' There is determination there. There is activism," Arad said.