Michael B. Oren, who served as Israel’s ambassador to the U.S. during the early Obama administration, said President Joe Biden’s support for the Jewish state in the wake of the Hamas attack that killed 1,200 people in southern Israel is deeply appreciated, but he now senses a wavering in that backing.

Oren on Friday gave a brief interview to The Denver Gazette as he signed copies of his new book, 2048: The Rejuvenated State, for attendees at the Jewish National Fund-USA’s global conference at Colorado Convention Center.

“It’s an existential crisis,” Oren told The Denver Gazette. “We’ve never had crises that were close to existential.

“The Yom Kippur War was close, the intifada was close,” Oren continued.

But the situation, which will soon enter its third month, contains threats that add layers of complexity beyond what Israel has confronted before, he said.

“We have 137 hostages, so we can’t just go into Gaza and destroy Hamas,” Oren said. “We have the power but we can’t do it.”

“If we don’t destroy Hamas we have no security,” he added. “Parts of Israel become uninhabitable.”

Oren said he deeply appreciates Biden’s backing following the attack, but he worries about the future.

“So far (the Biden administration’s support) has been excellent, but I don’t know how long they can withstand the pressure. They’re under immense pressure,” Oren said.

“I see them wavering,” he continued. “(Secretary of State Antony) Blinken’s remarks today were signs of wavering.”

Blinken was quoted in press reports yesterday as having told the Israeli government that it needs to avoid displacing Palestinians and damaging civilian infrastructure, such as hospitals and power stations, in its pursuit of Hamas. Oren said that the secretary also conveyed a need to speed up the operation.

“He said Israel has to step up the operation and cut down the Palestinian casualties,” Oren said. “You can’t do both because if we go faster we’re going to cause more casualties.”

Oren said he admires Blinken and has a warm relationship with him. However, he said the message the Biden official conveyed amounts to “impossible demand on us.”

Oren said although Israeli military superiority would make a quick victory possible, such an attack would never be carried out.

Oren, who was born in New Jersey and who moved to Israel in 1979 and later served in the IDF and in the Knesset, urged Americans to explore the complex moral decisions that confront a nation following such an attack.

“There was a rocket over Tel Aviv today,” he said. “You put a couple of rockets over Denver and see what the United States Army would do.”