Nikki Haley, the former ambassador to the United Nations, launched a scathing series of attacks on former President Donald J. Trump on Saturday, questioning the former president’s capacity to manage the foreign affairs of a country facing multiple military entanglements abroad.
In remarks before a gathering of Jewish Republicans in Las Vegas, Ms. Haley highlighted remarks by Mr. Trump criticizing Israeli intelligence and Prime Minister Benjamin Netanyahu as weak just days after the attack.
“As president, I will not compliment Hezbollah. Nor will I criticize Israel’s prime minister in the middle of tragedy and war. We have no time for personal vendettas,” she told the crowd of nearly 1,500 donors, activists and officials. “With all due respect, I don’t get confused.”
The comments were one of the most aggressive attacks from any 2024 candidate on Mr. Trump, the dominant front-runner, since the start of the primary contest. Ms. Haley questioned whether the former president, a polarizing figure since the start of his primary campaign eight years ago, could defeat President Biden in the general election next November.
“Eight years ago, it was good to have a leader who broke things. But right now, we need a leader who also knows how to put things back together,” she said. “America needs a captain who will steady the ship, not capsize it. And Republicans need a candidate who can actually win.”
Her broadside came shortly after another candidate — former Vice President Mike Pence — announced the end of his presidential bid.
“It’s become clear to me that this is not my time,” he said, offering a plea to his party to resist the “siren song of populism” and foreign policy isolationism.
Mr. Trump entered Saturday’s event as the crowd favorite, beloved for his record on Israel as president, which included moving the American embassy to Jerusalem and signing the Abraham Accords, an agreement normalizing relations between Israel, the United Arab Emirates and Bahrain. He also cut aid for Palestinians, and his administration took steps to designate a campaign to boycott Israel as antisemitic.
But Ms. Haley, known for her staunch support of Israel as Trump’s ambassador to the United Nations, has been climbing in the polls after two strong debate performances.
The annual gathering of the Republican Jewish Coalition has become perhaps the highest-profile gathering of the Republican primary season, taking on greater urgency after Hamas’s attack on Israel three weeks ago.
It is also a galvanizing moment for Republican officials: In a last-minute pivot, the event’s schedule changed to accommodate the first national appearance by the newly elected House speaker, Mike Johnson, who will address the group on Saturday night.
Support for Israel unifies a broad coalition of Republican voters and officials, including foreign policy hawks, business leaders and evangelical Christians.
The war has become a dominant issue on the presidential campaign trail, and discussion of it has been omnipresent at the coalition event, which began on Friday at the sprawling convention center at the Venetian in Las Vegas.
Over a Shabbat dinner on Friday night, several Republican officials pledged their support for Israel and the Jewish people before an audience of 1,500 donors, activists and officials.
“Here in Nevada, we stand unequivocally and unapologetically with Israel and the Jewish community,” Gov. Joe Lombardo of Nevada said.
Amid the expression of concern and solidarity for one of America’s closest allies, in speeches on Friday — and in the prepared remarks of several candidates on Saturday — Republican politicians saw political opportunities in the divisions that the conflict has opened up at home.
Several of the speakers Friday night disparaged progressive Democratic lawmakers who have called for a cease-fire, including Representatives Ilhan Omar and Rashida Tlaib, whose names drew loud boos from the audience. Others spoke about the tensions on college campuses, where students have clashed over the war.
Representative David Kustoff, a Republican from Tennessee, said that after the attacks, a number of American Jews went “to bed as progressives and woke up the next morning as conservatives.”
The speeches offered a preview of the kind of attacks Republicans might lob at President Biden next year, questioning whether his administration was prepared for the conflict in the Middle East and highlighting divides between his party’s progressive wing and the administration.
“We all know ‘The Squad’ and many Democrats hate Israel. No surprise there,” said Senator Rick Scott of Florida, who also took aim at Mr. Biden, accusing the president of “aimlessly supporting everything and nothing.”