Hillary Clinton used her speech Monday at the American Israel Public Affairs Committee (AIPAC) conference to attack Republican presidential front-runner candidate Donald Trump, who was set to address the pro-Israel lobbying group later that evening. The former secretary of state promised to bring America and Israel closer together if elected president. Though she did not name Trump, she said when it comes to Israel’s security, the U.S. cannot afford to be “neutral,” as the New York businessman has said he would be.

“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,” Clinton said, referencing a quote from Trump about his varying stances. “Well my friends, Israel’s security is non-negotiable.”

The conference marks the first time Clinton and Trump will address the same group, giving what many expect to be a general election preview on the two candidates’ foreign policy positions. Clinton touted her experience dealing with Middle East peace negotiations in the past and stressed the importance of a close relationship with Israel amid rising terror threats around the world.

“The United States and Israel must be closer than ever, stronger than ever and more determined than ever to prevail against our common adversaries and to advance our shared values,” Clinton said during her speech. “The next president will sit down at that desk and start making decisions that will affect both the lives and livelihoods of every American and the security of our friends around the world. So we have to get this right.”

Clinton spent time talking about the need for American Jews to defend Israel and for Israel to commit to peace negotiations, but she also spoke more broadly about the 2016 election and the leading GOP presidential candidate. Trump’s proposed policies were a focal point of Clinton's speech, which seemingly compared his ideas to those of Adolf Hitler. She mentioned Trump's tendency to encourage violence, “playing coy with white supremacists,” wanting to turn away refugees because of their religion and deporting immigrants living in the United States.

“We’ve had dark chapters of our history before. We remember the nearly 1,000 Jews aboard the St. Louis who were refused entry in 1939,” she said, referring to the German ship that was forced to return to Europe that year with more than 900 Jewish refugees on board.

“America should be better than this, and I believe it is our responsibility as citizens to say so,” Clinton added. “If you see bigotry, oppose it. If you see violence, condemn it. If you see a bully, stand up to him.”

While Trump is expected to address AIPAC Monday evening, some Jewish leaders are not happy about the Republican’s invitation to the annual event. He has routinely made anti-Muslim and anti-immigrant comments, and many Jews were uncomfortable when Trump initially declined to disavow the support of the former Ku Klux Klan leader David Duke. Several groups of rabbis and other Jewish religious leaders planned to protest Trump’s speech at the Israel conference, and his comments are highly anticipated after he ruffled feathers last year by relying on Jewish stereotypes when speaking to the Republican Jewish Coalition, a group of influential Jewish donors.