Biden's big Middle East fear comes true

President Biden has spent nearly a year plotting and praying he could help prevent the war in Gaza from spreading. The rapidly expanding conflict between Israel and Hezbollah signals his power has reached its limit.

Why it matters: U.S. officials privately admit the massive fighting that's killed more than 700 people in Lebanon looks like another war — even if the Biden administration doesn't officially call it one.

Driving the news: White House deputy national security adviser Jon Finer in an Axios event on Tuesday said the airstrikes and rocket attacks between Israel and Hezbollah could get much worse.

• "There is a conflict in Lebanon... but that could be a much bigger war and what we are extremely concerned about is a much bigger war, a wider war," Finer said.
• "A bigger war is not in the interest of Israel and will not allow people to go back home," he added.

But Finer said that while the war in Gaza has spilled over, it wasn't to the degree people in the region and around the world feared.

• He said the U.S. should be credited for the steps it took, including Biden's public threats to Iran and the significant boosting of U.S. forces in the Middle East, which included two aircraft carrier strike groups that were positioned in the region for months.

The big picture: After Hezbollah began launching attacks against Israel on Oct. 8 in solidarity with Palestinians, the U.S. tried to contain the conflict and keep it to skirmishes along the Israel-Lebanon border.

• U.S. officials began working on a diplomatic solution in an attempt to stop the fighting, push Hezbollah's forces back from the border and allow tens of thousands of civilians to return to their homes on both sides of the border.
• But as the war in Gaza continued, the skirmishes between Israel and Hezbollah slowly and gradually escalated. Each side attacked targets deeper into the other's territory, using heavier and more sophisticated weapons.

In recent months, Biden's senior adviser Amos Hochstein made progress toward a deal to calm the border conflict, but it was contingent on reaching an agreement to release hostages held by Hamas and establish a ceasefire in Gaza.

• When the hostage-ceasefire negotiations deadlocked a few weeks ago, Hochstein's initiative stalled out with it.
• A day after Hochstein traveled to Israel last week and warned Netanyahu of the negative consequences of a war in Lebanon, Israel conducted the first in a series of deadly attacks, remotely detonating pagers carried by Hezbollah members.
• Hochstein was livid — not only because the Israelis kept him in the dark about the attack, but because they completely ignored everything he told them, U.S. officials said.

State of play: While some of Biden's advisers saw the Israeli pager attack as "a reckless march to war," at the end of the day the White House accepted what the Israelis describe as a plan of "de-escalation through escalation," U.S. officials said.

• Some of Biden's aides agreed with the logic of Israel's leaders.
• Others concluded U.S. influence on Israel's decision making is now limited.

Now, the U.S. objective is to prevent an Israeli ground invasion of Lebanon and deter Iran from intervening and supporting Hezbollah, U.S. officials said.

• The Biden administration told the Israeli government it opposes an Israel Defense Forces ground operation in southern Lebanon, U.S. officials said.
• "We want to prevent a ground war," a senior U.S. official said, re-calibrating the Biden administration's focus on what might still be achievable.

Between the lines: Even though Hezbollah is its closest and most powerful proxy force, the Iranians are very hesitant at the moment to get directly involved in the fighting in Lebanon, U.S. officials said.

• But Iran has vowed to retaliate for the assassination of Hamas leader Ismail Haniyeh by Israel in Tehran two months ago and U.S. officials don't rule out that the Iranians will attack Israel at some point.
• "We defended Israel against the Iranian attack in April and we stand ready to do it again Iran tries to attack Israel," Finer said.

What to watch: Biden's top advisers are spending the next few days in New York on the sidelines of the UN General Assembly to try to find a diplomatic solution to stop the fighting in Lebanon.

• Lebanese Prime Minister Najib Mikati arrived in New York on Tuesday night and Israel Prime Minister Benjamin Netanyahu is expected to arrive in New York on Thursday morning.
• "We see a path to de-escalating the situation in the north and we are working on it in real time in New York and in capitals around the world," Finer said.