The history of Americans support for Israel in and out

With President Joe Biden pledging unwavering support of Israel in its fight against the Hamas terror group, he's the latest U.S. leader promising the United States' commitment -- an allegiance dating back to the Jewish state's inception 75 years ago when President Harry S. Truman became one of the first world leaders to embrace the creation of the democratic country in the Middle East.

"If you think of American history in the 20th Century and in the 21st Century, America's enemies and Israel's enemies were the same, whether it was Nazism, whether it was communism, whether it was Islamist extremism," David Makovsky, director and senior fellow on Arab-Israel relations at the Washington Institute for Near East Policy, a pro-Israeli American think tank in Washington, D.C., told ABC News.

Mark Mellman, president of the Democratic Majority for Israel, a U.S. organization that works to maintain and strengthen support for the U.S.-Israel alliance, said the friendship between the two countries was borne out of the United States' effort to secure allies during the Cold War.

"America wanted allies, as many as we could get, and Israel was one of them," Mellman told ABC News. "But there's also ... a long historical affinity, a belief that the Jewish people have a right to a state and a right to a homeland, in their historic homelands, which had been the homeland of the Jewish people for thousands of years. And that sort of biblical perspective, if you will, animated some Americans in this respect. But basically, we had two countries that had similar values and similar interests. Those have been the things that have really brought the United States and Israel so very close together."

Mellman added, "There has always been an important level of bipartisan support for Israel. Both Democrats and Republicans have long been pro-Israel."

However, there has also been a growing chorus of critics of Biden during his tenure, most prominently among progressive Democrats, including Michigan Rep. Rashida Tlaib, who was censured by her House colleagues for using a phrase that some said endorsed wiping the state of Israel off the map -- an interpretation that Tlaib has denied.

"From the river to the sea is an aspirational call for freedom, human rights, and peaceful coexistence, not death, destruction, or hate," Tlaib said in a statement on X. "My work and advocacy is always centered in justice and dignity for all people no matter faith or ethnicity."

America's support for Israel comes as the country was attacked last month. The militant group Hamas launched a surprise attack on Israel on Oct. 7 and Israel retaliated with a bombing campaign and military operation in the neighboring Gaza Strip.

In Israel, at least 1,200 people have been killed and 6,900 others have been injured since the Oct. 7 attack, according to Israeli officials. In Gaza, at least 13,000 people have been killed and over 30,000 have been injured, according to the Hamas-run Gaza Health Ministry. That unfolding humanitarian crisis in Gaza has complicated the U.S. relationship with Israel.

As the war rages on, the sympathy of some Americans appears to be shifting from Israel to the Palestinians in Gaza. A Quinnipiac University national poll of registered American voters released on Nov. 16 found that overall 54% said their sympathies lie more with the Israelis, down from 61% in an Oct. 17 poll. Meanwhile, 24% of American voters said they were more sympathetic to Palestinians, up from 13% in the October survey.

Among Democrats, 41% said their sympathies lie more with the Palestinians, while 34% said their sympathies lie more with the Israelis. In October, 48% said they were sympathetic to the Israelis and 22 percent said the Palestinians, according to the Quinnipiac poll.

Among American voters 18 to 34 years old, 52% of respondents in the Nov. 16 Quinnipiac poll said their sympathies lie more with the Palestinians, while 29 percent said they were sympathetic to the Israelis. The numbers indicated a sharp reversal from October when 41% said the Israelis had their sympathies and 26% said they were sympathetic to the Palestinians.