WASHINGTON – Donald Trump’s stated willingness to enter Mideast peace talks from a position of neutrality make him unfit to be commander in chief, Hillary Clinton told a major pro-Israel group Monday.

Speaking from the same stage where Trump, the Republican front-runner, will address the American Israel Public Affairs Committee later Monday in Washington, Clinton alluded to a number of Trump’s broad pronouncements on foreign policy and especially the U.S. relationship with Israel.

Clinton, the former secretary of state, questioned Trump’s temperament as much as his overall foreign policy vision – or lack thereof. She warned against isolationist tendencies of Trump and others in the GOP.

“Candidates for president who think the United States can outsource Middle East security to dictators or that America no longer has vital national interests at stake in the region are dangerously wrong,” she said, adding that it would be a “serious mistake” for the U.S. to “cede the mantle of leadership for global peace and security to anyone else.”

“Yes, we need steady hands, not a president who says he’s neutral on Monday, pro-Israel on Tuesday, and who knows what on Wednesday, because everything’s negotiable,” she said.

“Some things aren’t negotiable,” she added later. “And anyone who doesn’t understand that has no business being our president.”

Trump’s precise views on foreign policy are, indeed, something of a moving target. In a recent Republican debate, Trump asserted that he was the most pro-Israel candidate but said he would enter negotiations between Israel and Palestinians, framing himself as “somewhat neutral” in hopes of reaching a peace deal.

Clinton reiterated her support for a two-state solution, saying that Palestinians “should be able to live and govern themselves,” even as she seemed to share Israel’s doubts that “a willing and capable partner for peace even exists.”

Clinton said one of her first acts as president would be to invite the Israeli prime minister to the White House. She downplayed the tensions between President Barack Obama and Prime Minister Benjamin Netanyahu, but said it was time to take the U.S.-Israel relationship to “the next level.”

She highlighted her role in building sanctions against Iran that paved the way for the historic nuclear agreement between Iran and six world powers – an Obama initiative that she said has made Israel, the United States and the world safer, and one she would vigorously enforce.

“There’s a big difference between talking about holding Tehran accountable and actually doing it,” she said. “Our next president has to be able to hold together our global coalition and impose real consequences for even the smallest violations.”

As Trump prepares to meet with some Republican lawmakers in Washington on Monday, Clinton closed with something of a challenge to the GOP as its leaders come to grips with the possibility that he will indeed lead the party ticket this fall.

Alluding to the caustic tone of the campaign, she said America has seen “dark chapters before.”

“But America should be better than this. And I believe it’s our responsibility as citizens to say so,” she said. “If you see bigotry, oppose it. If you see violence, condemn it. If you see a bully, stand up to him.”