President Biden must do more to rein in Prime Minister Netanyahu’s conduct in the Hamas war, allies of the commander-in-chief say, or risk losing support here at home. Those allies, including close friends and outside supporters, say Mr. Biden’s political standing will be harmed if policy changes are not made.

Following the death of seven aid workers with the nonprofit group World Central Kitchen, which was working to feed Gazans until the strike occurred, allies of the president have said protections for civilians and workers must be guaranteed before more support for Israel can be offered. Mr. Biden says he was “outraged” by the death of the aid workers. 

Most notably, the first lady has reportedly said that her husband needs to stop the Gaza operation as soon as possible. During a meeting with Arab-American and Muslim leaders at the White House on Wednesday, Mrs. Biden told an attendee that she had been urging the president to “stop it now,” according to the New York Times. 

The co-chairman of the Biden 2024 campaign and a close friend of the president, Senator Coons, now says he would be willing to condition aid to Israel after months of supporting the Jewish state’s military operations at Gaza. He says an invasion of Rafah without certain humanitarian guarantees would force him to do so. 

“If Benjamin Netanyahu were to order the IDF into Rafah at scale, [if] they were to drop thousand-pound bombs and send in a battalion to go after Hamas and make no provision for civilians or for humanitarian aid, I would vote to condition aid to Israel,” Mr. Coons said in an interview with CNN. “I’ve never said that before, I’ve never been here before. I’ve been a strong supporter of Israel the whole time I’ve served in Congress.”

Mr. Coons’s foray into a possible conditioning of aid puts him in company with Senator Sanders, who has been calling for such protections for months. “The Democratic base wants to stop funding for the Netanyahu war machine,” Mr. Sanders told MSNBC. “Is it going to hurt the president unless he turns this around? Yes, it will.”

Messrs. Biden and Sanders were the last two men standing for the 2020 Democratic presidential nomination, but they have become close in recent years. Just on Wednesday, the president and the Vermonter held an event at the White House to tout drug pricing reform. 

Mr. Biden’s supporters beyond Capitol Hill also say the president’s response to the aid workers’ deaths has not been sufficient. 

A former president of the Council on Foreign Relations, Richard Haass, appeared on the president’s favorite television show, MSNBC’s “Morning Joe,” to say that sanctions on Israel may be needed. He says Mr. Biden’s “criticism” of Mr. Netanyahu “looks increasingly empty.”

“At some point the words become empty, and the Biden administration is very close to having reached a point where their criticism of Israel is too much for the same people who criticized Chuck Schumer, but it’s not nearly enough to affect the course of what is going on. That is the worst of all possible worlds,” he said. 

“This administration has got to have some teeth in it,” Mr. Haass continued. 

An advisor to Secretary Rice, Elise Jordan, echoed those sentiments. “It looks weak and impotent,” Ms. Jordan said of the president’s harsh rhetoric but lack of policy change. 

On Thursday, the president spoke with Mr. Netanyahu about civilian and aid workers’ deaths at Gaza. Mr. Biden “emphasized that the strikes on humanitarian workers and the overall humanitarian situation are unacceptable. He made clear the need for Israel to announce and implement a series of specific, concrete, and measurable steps to address civilian harm, humanitarian suffering, and the safety of aid workers,” according to a White House readout of the leaders’ phone call.