Donald Trump’s comments about remaining “neutral” in the Israeli-Palestinian conflict should not be easily dismissed, Democratic presidential candidate Hillary Clinton said on Thursday.

“It is no small thing when [Donald Trump] says he will stay neutral on Israel’s security,” Clinton said during a major national security address in San Diego on Thursday, in which she labeled Trump as “temperamentally unfit” to serve as president and called his ideas “dangerously incoherent.”

“Israel’s security is non-negotiable,” she declared. “They are our closest ally in the region, and we have a moral obligation to defend them.”

Clinton also touted her role in leading the effort to impose crippling sanctions on Iran and defended the nuclear deal “that should block every path for Iran to get a nuclear weapon.”

“There is no question that the world and the United States, we are safer now than we were before this agreement,” she stressed. “And we accomplished it without firing a single shot, dropping a single bomb or putting a single American soldier in harm’s way.”

“Now we must enforce that deal vigorously. And as I have said many times before, our approach must be distrust and verify,” she said. “The world must understand that the United States will act decisively if necessary, including with military action, to stop Iran from getting a nuclear weapon.”

The former Secretary of State challenged the presumptive Republican nominee to offer an alternative in the absence of a nuclear deal he’s opposed to. “Donald Trump says we shouldn’t have done the deal. We should have walked away. But that would have meant no more global sanctions, and Iran resuming their nuclear program and the world blaming us. So then what? War? Telling the world, good luck, you deal with Iran?” she asked rhetorically.

“There’s no risk of people losing their lives if you blow up a golf-course deal. Donald Trump doesn’t know the first thing about Iran or its nuclear program. Ask him. It will become very clear, very quickly,” she suggested.

In her 30-minute address, Clinton said the election in the fall “is a choice between a fearful America that is less secure and less engaged with the world, and a strong America that leads to keep us safe and our economy going.”

Noting her tenure as secretary of state, mentioning her success in brokering a ceasefire between Israel and Hamas, among others, Clinton said, “I’m not new to this work, and I’m proud to run on my record, because I think the choice before the American people in this election is clear. Making Donald Trump commander-in-chief would be a historic mistake.”