Israel had planned to strike Iranian nuclear sites as soon as next month but was waved off by President Trump in recent weeks in favor of negotiating a deal with Tehran to limit its nuclear program, according to administration officials and others briefed on the discussions.

Mr. Trump made his decision after months of internal debate over whether to pursue diplomacy or support Israel in seeking to set back Iran’s ability to build a bomb, at a time when Iran has been weakened militarily and economically.

The debate highlighted fault lines between historically hawkish American cabinet officials and other aides more skeptical that a military assault on Iran could destroy the country’s nuclear ambitions and avoid a larger war. It resulted in a rough consensus, for now, against military action, with Iran signaling a willingness to negotiate.

Israeli officials had recently developed plans to attack Iranian nuclear sites in May. They were prepared to carry them out, and at times were optimistic that the United States would sign off. The goal of the proposals, according to officials briefed on them, was to set back Tehran’s ability to develop a nuclear weapon by a year or more.

Almost all of the plans would have required U.S. help not just to defend Israel from Iranian retaliation, but also to ensure that an Israeli attack was successful, making the United States a central part of the attack itself.

For now, Mr. Trump has chosen diplomacy over military action. In his first term, he tore up the Iran nuclear deal negotiated by the Obama administration. But in his second term, eager to avoid being sucked into another war in the Middle East, he has opened negotiations with Tehran, giving it a deadline of just a few months to negotiate a deal over its nuclear program.