David M. Friedman, the United States ambassador to Israel, said Mr. Abbas had “reached a new low,” adding, “To all those who think Israel is the reason that we don’t have peace, think again.”

Mr. Abbas is presiding over the first regular meeting of the Palestine National Council in 22 years. It may well be his last. (The council convened for a more limited, “extraordinary” session in 2009 to replace six members of its 18-member executive committee who had died in the meantime.)

On the eve of the four-day gathering of about 700 council delegates in Ramallah, an Abbas adviser promoted it as a historic meeting dedicated to Palestinian unity, democracy and setting strategy for the coming months and years.

It seemed to have started out as anything but that.

Instead, it was taking place with a deeply splintered Palestinian leadership that has turned away from Washington because of President Trump’s decision to recognize Jerusalem as the capital of Israel and is largely disconnected from its own public. A March opinion poll found that 68 percent of Palestinians want Mr. Abbas to resign from office.

The Palestinian Authority has looked on while its archrival, Hamas, the Islamist militant group that controls Gaza, has seized the popular initiative and focused international attention on the isolated and impoverished coastal enclave with its promotion of the so-called Great Return March. More than 40 Palestinians have been killed and hundreds have been wounded, many shot in the legs, by Israeli snipers over the past month during partly peaceful, partly violent protests along the Gaza border.

Mr. Abbas has long advocated nonviolent popular resistance against the Israeli occupation but is also wary of protests, fearing they could spiral out of control and be detrimental to the cause, or even turn against him, according to experts.

So he has found himself in the awkward position of trying to both pay lip service to, and dampen the enthusiasm for, the Gaza protests. In his speech he warned the children of Gaza to stay away from the border fence because “I do not want a disabled generation.”