Biden appears to have given Israeli Prime Minister Benjamin Netanyahu a free hand, for now, to press his war against Hamas, though a threatened ground offensive - with the likelihood of a higher civilian death toll - could force the president to rethink that approach.
As Biden vows rock-solid support for Israel, he has only faced scattered protest from the left wing of the Democratic Party over his acquiescence to Israel's tough crackdown in the crowded coastal strip.
Leading Democrats have helped him keep a lid on any intra-party dissent, seeking to project a message of unity, despite calls from a few progressives to get Israel to act with restraint to avoid massive civilian casualties as it battles Hamas.
The international outcry mounted on Friday against Israel's warning to more than a million Gaza civilians to evacuate south within 24 hours before an expected all-out assault.
In Washington, however, Biden's allies want to avoid giving Republicans an opening to accuse him of undercutting US ally Israel's military response, which could make the crisis a political liability as he seeks re-election in 2024.
Republicans have shown near-unanimity in backing whatever military action Israel decides to take after suffering the deadliest attack on its soil in decades. More than 1,000 people were killed and dozens more abducted into Gaza, including Americans.
Israeli strikes on Gaza having killed more than 1,000 people, preparations under way for a ground invasion and Israeli leaders vowing to annihilate Hamas, those voices could easily get louder in the days to come.
As Democratic leaders excoriate Hamas and pledge support for Israel, some have already injected carefully worded reminders of the need for Israel to abide by the laws of war.
"We are going to stand by Israel and make sure that we defend them and give them what they need to defend themselves," said US Representative Gregory Meeks, the ranking Democrat on the House Foreign Relations Committee.
But with militants using ordinary Palestinians as human shields, he said, "we must keep these Palestinian people and their safety and livelihood in mind as we crush Hamas.”
For much of Congress as well as the American public, Israel's likening of the devastating Hamas assault to the September 11, 2001, hijacking attacks on New York and Washington has resonated widely.
US Representative Rashida Tlaib, the only Palestinian-American in Congress, this week issued a statement that drew criticism for saying she grieves for both Palestinian and Israeli lives lost.
In a tough message to Israel, she said the path forward must include lifting the blockade, ending the occupation, and dismantling the apartheid system that creates the suffocating, dehumanizing conditions that can lead to resistance.
Responding to a question about early criticism of Israel’s response by other liberal lawmakers who had equated the Hamas attack with past Israeli actions, White House Press Secretary Karine Jean-Pierre denounced such statements as repugnant.
“Our condemnation belongs squarely with terrorists,” she told reporters on Tuesday.
On Friday, US Representative Alexandria Ocasio-Cortez, a Democratic progressive who had strongly condemned the Hamas attack, assailed Israel over its Gaza evacuation order as unacceptable, saying on the social media platform X, "We must halt this."
