WASHINGTON >> Hillary Clinton and Donald J. Trump on Monday presented sharply different views on how the United States should deal with the Middle East and its relationship with Israel, previewing for an influential pro-Israel audience a debate on foreign policy that could play out this fall if they face each other in the general election.

Clinton promised she would stand unwaveringly with Israel while accusing her potential Republican rival, Trump, of being an unreliable partner for one of America’s closest allies. “We need steady hands,” she said, “not a president who says he’s neutral on Monday, pro-Israel on Tuesday, and who-knows-what on Wednesday.”

Speaking to the same audience hours later, Trump swore his fealty to Israel and condemned President Barack Obama’s policies. But Trump, who describes himself as a “master counterpuncher,” declined to answer Clinton’s criticisms, offering a standard appeal to a pro-Israel audience. “When I become president,” he said, “the days of treating Israel like a second-class citizen will end on Day 1.”

Trump’s remarks, which came after he had sent a series of conflicting signals about Israel on the campaign trail in recent weeks, drew less sustained applause than Clinton’s from the crowd of 18,000 people assembled by the American Israel Public Affairs Committee, the nation’s most influential pro-Israel lobbying group.

The competing speeches not only made for rich political theater, but they also vaulted the presidential campaign into a new phase, in which Trump and Clinton seemed to be turning from their primary battles to the general election. And they thrust America’s complicated relationship with Israel to the forefront of the campaign.

Clinton, the former secretary of state and the Democratic front-runner, wasted no time taking aim at Trump for declaring recently that he would be “neutral” when it came to negotiating a peace accord between the Israelis and Palestinians. While Trump’s remark did not stray far from traditional American policy, his blunt language rattled some in Israel, who worry that it might portend a less supportive United States.

“America can’t ever be neutral when it comes to Israel’s security and survival,” Clinton declared. “My friends, Israel’s security is non-negotiable.”

Clinton offered a thunderous affirmation of American solidarity with Israel, with promises to buttress Israel’s military, combat anti-Semitism, press Iran to abide by its nuclear agreement with the West, crack down on Iranian proxies like Hezbollah and thwart efforts to boycott Israeli products.

“We must repudiate all efforts to malign, isolate and impugn Israel and the Jewish people,” she said.

Clinton also played up her credentials to be commander in chief and accused the Republican candidates of lacking either the experience or the will to extend American leadership in the Middle East. “We have to get this right,” she said.

Trump, ahead in the Republican race but opposed by many parts of the party, focused heavily on Iran, promising to dismantle the nuclear deal negotiated by Obama, thwart what he described as Iran’s efforts to destabilize the Middle East and punish Iran for testing ballistic missiles. “Nobody has done anything about it,” he said to cheers. “We will. We will.”

Trump’s aides released text of the prepared remarks he used, something he almost never does on the campaign trail. They contained one tempered reference to Clinton, but he ad-libbed another: “Hillary Clinton, who is a total disaster by the way, she and President Obama have treated Israel very, very badly,” he said.

But he raised eyebrows in the audience at the Verizon Center when he referred repeatedly to Palestine. Sen. Ted Cruz, the Texas Republican who spoke after Trump, noted pointedly that “Palestine has not existed since 1948.”

Cruz’s speech ended a day of presidential politics at the AIPAC conference. In addition to Cruz and Trump, another Republican, Gov. John Kasich of Ohio also spoke, declaring himself an unshakable friend of Israel, who would also tear up Obama’s nuclear deal with Iran.

Referring to the Republican lineup later in the day, Clinton said it would give a glimpse of a foreign policy that would “insult our allies” and “embolden our adversaries.”

Clinton declared that she would allow no daylight between the United States and Israel on the peace process. But she opened some daylight with the White House, reiterating her opposition to any U.N. Security Council resolution that would seek to impose the contours of a two-state solution. Obama is contemplating such a move before he leaves office, though he may instead opt to lay down parameters for a deal in a speech.

“I would vigorously oppose an attempt by any outside party to impose a solution, including by the United Nations Security Council,” she said.

Clinton reaffirmed her support for Obama’s nuclear deal with Iran, but she repeated her warning that she would use military force, if necessary, to punish Iran for violating the terms of the agreement.

Trump’s appearance at AIPAC upset some Jewish groups. When he was asked on CNN about reports that some rabbis intended to boycott his speech because of comments seen as bigoted, Trump replied: “We have to be careful. We have to be careful who we allow into the country.”

Still, while protesters have appeared at most of his recent rallies, Trump delivered his remarks uninterrupted. He stuck to tried-and-true formulations during his speech. Near the end, he noted that his daughter Ivanka “is about to have a beautiful Jewish baby.” The remarks reflected Trump’s genuine frustration at being labeled anti-Semitic by some critics.

Earlier in the day, at a news conference at his new hotel in downtown Washington, Trump appeared to suggest that Israel should be made to pay more for its own defense. A reporter pointed out that normally at his rallies, he demands that countries like Germany receive foreign aid and suggests that they can defend themselves, and then asked if the same standard should apply to Israel.

“I think Israel will do that also, yeah,” Trump said. “I think Israel will do — there are many countries that can pay and they can pay big league. I mean, we’re supporting South Korea. I order thousands of television sets a year from South Korea. They’re a behemoth economically. Every time North Korea raises its head they do anything, they sneeze.”

But when reporters pressed him to clarify later, he suggested that it should be assessed on a case-by-case basis, and that Israel had special status. “Israel helps us in the Middle East,” Trump said. “Israel helps us greatly in the Middle East. It’s our one ally that we really can count on.”

Clinton is a familiar figure at these meetings, though she does not always bear as reassuring a message as she did on Monday. In March 2010, while serving as secretary of state, she sharply criticized the Israeli authorities for approving new Jewish housing in an Arab neighborhood of East Jerusalem at a sensitive moment, when the United States was trying to get the Israelis and Palestinians back to the negotiating table.

In that speech, which was less warmly received than Monday’s, Clinton described the American role in the peace process as, if not neutral, than as an honest broker between the two sides. “Our credibility in this process,” she said, “depends in part on our willingness to praise both sides when they are courageous, and when we don’t agree, to say so, and say so unequivocally.”

Clinton’s Democratic rival, Sen. Bernie Sanders of Vermont, was the only presidential candidate who did not address the conference. A senior official at AIPAC said Sanders had been invited to speak but could not come to Washington because of his campaign schedule. In a change of policy this year, AIPAC did not allow presidential candidates to speak to the group by satellite.

© 2016 The New York Times Company