Money.

The history of the conflict is pretty complicated. As far as US support goes, the US can utilize Israel and wars as a destabilizing force in middle east which is beneficial to the Military Industrial Complex, and influence in the region with Hard/Soft Power. Reductively, because of Money and Power.

Following Israel’s stunning victory and occupation of Gaza, the West Bank and East Jerusalem, Washington concluded that Arab nations had moved into the Soviet camp and so increased weapons sales to the Jewish state, including Phantom jet fighters.

Initially as an anti Soviet position under LBJ

Military support for Israel solidified under the Reagan administration which also began a more vigorous diplomatic defence of Israel – particularly shielding it from criticism at the United Nations.

And especially to sell weapons under Reagan

https://www.theguardian.com/us-news/2023/nov/16/why-israel-allies-explainer

The US has been supporting the ethnic cleansing of Palestine since the 1967 war and the occupation of Gaza and the West Bank, and that position has led to the US supporting the ongoing genocide in Gaza today.

Biden is also a strong Zionist, so... There's that too

Biden isn’t a genocidal maniacBack during the Iraq War, Biden and Blinken came up with the idea of partitioning Iraq into 3 different ethnostates. "We should take [ethnic group] and PUSH it somewhere else!!" is the kind of thing Biden thinks makes sense.

"It is important that whatever you do succeeds quickly. We would be able to influence the reaction in America if whatever happens happens after we return."

you really need to go back and look at the history of post WWII. How that cookie crumbled has set the world stage for where it is today. Israel is part of a long term geopolitical chess game that hasn't fully played out yet.

Israel is an ally in the middle east, the only one who does what the US says whenever they say it.