How big is this going to get? What to watch for in the Israel-Hamas battle.

President Joe Biden and his aides have long tried to bring some calm to the Middle East, in large part so that the United States could focus more intensely on the greater long-term challenge: China. That strategy is now in danger due to this weekend’s stunning attack on Israel by the Palestinian militants of Hamas.

As Israel retaliates, the possibility of a wider regional war looms, demanding more of Biden’s attention. Hundreds of people have died. Biden and his team will inevitably have less bandwidth to focus on Beijing. And that’s as the Biden administration’s attention already is stretched due to Russia’s war in Ukraine.

It’s a frustrating dynamic for a White House that had notched what it believed were major, often unsung successes in the Middle East. (And hardly a novel one: Many presidents trying to focus their efforts elsewhere have been vexed by the Middle East.) That included freezing the war in Yemen and making headway on pre-existing efforts to help Israel build diplomatic, economic and other ties with once-hostile Arab states; even the Palestinians had gotten involved. The Biden team described the strategy as promoting regional “integration”, but the conflict threatens an unraveling.

Still, it’s early days, so there are many more questions than answers. Here are some that national security professionals in Washington and beyond are pondering:

How big will this get?

What’s now a fight between Israel and Hamas has the potential to turn into a wider war, convulsing a region that hosts many rivalries — and many U.S. troops.

Hamas may long for its Iranian backers and sympathetic Arab governments to come to its direct aid. Other armed groups, including Lebanon-based Hezbollah, could provide manpower or seize the moment to spur violence elsewhere. There were reports Sunday that Hezbollah had fired mortar shells at Israeli positions.

The fighting could also spread beyond the Hamas-controlled Gaza Strip and to the West Bank. There, tensions between Palestinians and Israelis have risen as Israel has built more settlements on land claimed by Palestinians.

But each government or group also has incentives to avoid the fray, including not wanting to endanger ties with Washington or spill blood and treasure on a war with no clear endgame.

American officials are scrambling to contain the fighting. Biden on Saturday warned “against any other party hostile to Israel seeking advantage in this situation.” His aides, meanwhile, are burning up the phones.

“Anyone who has influence one way or the other has been spoken with,” said a U.S. official familiar with the issue who, like others, was granted anonymity to discuss a sensitive issue.

Israel warned other hostile actors not to get involved. “The expansion of the arena of combat against Israel will be met with a particularly harsh response, including determined and lethal actions by Israel,” an Israeli official said.

Is Iran to blame?

Some hawks in Washington and beyond have been quick to label Tehran as the true culprit behind the Hamas attack. Iran, after all, has long financially and militarily aided Hamas.

A Hamas spokesperson reportedly said Iran supported the weekend attack, and Iranian officials have cheered it. A Wall Street Journal report Sunday, citing senior members of Hamas and Hezbollah, said Iranian security officials had helped plan the attack.

But groups like Hamas do retain a certain level of independence from Tehran, and U.S. officials have yet to cast blame on Iran.

“At this moment, we don’t have anything that shows us that Iran was directly involved in this attack, in planning it or in carrying it out, but that’s something we’re looking at very carefully,” Secretary of State Antony Blinken said Sunday morning on NBC’s Meet the Press.

This doesn’t mean that Iran will walk away without repercussions. The United States could, for instance, impose new sanctions on Tehran on account of its general support for Hamas.

Will the Saudi-Israel dance end?

The Hamas attack threatens a U.S.-backed peace initiative that would see Saudi Arabia normalize diplomatic relations with Israel in exchange for U.S. security guarantees and other favors.

But it’s too soon to say the plan is derailed, though it will be delayed.

As Hamas attacked, Saudi Arabia and other Arab states issued statements more sympathetic to the Palestinians than Israel. But such immediate responses do not eclipse other factors the Saudis, Israel and the United States consider in crafting a grand peace deal.

Saudi Crown Prince Mohammed Bin Salman is not as fixated on the Palestinian crisis as past Saudi leaders. Like Israel, he sees Iran — a major Hamas backer — as a threat to his country. Saudi Arabia and Israel already informally cooperate on Iran; making their ties official strengthens the anti-Tehran bulwark.

Israel already has struck diplomatic normalization deals with Bahrain, the United Arab Emirates and Morocco. It has many incentives — including economic — to strike such a deal with Saudi Arabia, home to the holiest sites of Islam.

For the United States, anything that brings more calm to the Middle East is welcome for reasons that affect policies ranging from counterterrorism to energy. Another major factor is a desire by Washington to offset growing Chinese influence in the Middle East.

“China is not just showing up. They are showing up with massive, massive offers to these countries,” a senior Biden administration official told POLITICO last week, before the Hamas attack. The official declined to detail the shape of the grand bargain, including what security guarantees the U.S. would offer the Saudis.

The official also said Palestinians had been participating.

”They want to be a part of this process, and we would not do it without them,” the official said. “That is a major change from their policy, which has been they will never engage in any process that has to do with an Arab state normalizing relations with Israel absent a Palestinian state.”

The official didn’t specify which Palestinians, but the reference was likely to people affiliated with the Palestinian Authority.

That body, which governs in the West Bank, is a weak rival to Hamas and an ongoing agitator against Israel. But its fate may be affected by the new fighting. After all, noted one former senior State Department official, there is “the question of who rules Gaza when this is done.”

How did Israel not see this coming?

There’s no quick answer to the glaring question of how such a sophisticated, multipronged Hamas attack could happen without Israel’s vast intelligence apparatus —or that of the U.S.—seeing it ahead of time.

“There will be some kind of national commission of inquiry as to the intelligence failures that occurred,” Jonathan Schanzer of the Foundation for Defense of Democracies predicted.

Schanzer said the conventional thinking in Israel is that Hamas has always been a “tactical” threat — serious, but not one that could end the viability of Israel. But maybe Israel didn’t fully appreciate that Hamas, with help from Iran, had evolved into a more strategic threat, Schanzer said.

Israel fought with Hamas in 2021, taking out numerous targets of the militant group in Gaza over 11 days that left at least 260 Palestinians and a dozen Israelis dead. Is it possible it ended that fight too quickly — before it had done enough damage to Hamas’ capabilities?

The United States at the time made a concerted effort to convince Israel to limit the operation’s length. Still, Israel also had reached a point of diminishing returns when it came to the number of targets it could hit, Schanzer said.

This round of fighting could last much longer than 11 days, not least because Israel may stage a ground incursion and because Hamas is holding numerous hostages.

Will this affect Ukraine?

The United States already is ramping up its provision of military equipment, munitions and other resources to Israel. It’s also deploying ships and aircraft near Israel in a show of support.

The moves come amid a partisan fight over whether Washington should keep providing military and economic aid to Ukraine as it battles Russia’s invasion.

Republicans who have expressed growing misgivings about ongoing support for Ukraine quickly spoke in favor of aiding Israel. (The latter is a top cause for evangelical Christians who make up a notable chunk of the GOP base.)

For now, U.S. officials insist that aiding Israel on the military front won’t affect the aid to Ukraine. Different systems are involved in many cases.

Ukrainians may be disappointed in how America treats them versus Israel, a country whose military might they hope to echo. It doesn’t help that Israel has not offered Ukraine as much support as it could, chilling their relations.

Israel has refused to send the Iron Dome, an air defense system, to Ukraine to help protect its civilians and military positions from Russian attacks.

What about China’s role?

Earlier this year, Chinese officials said they’d be willing to make a run at peace talks between Israelis and Palestinians. This followed a successful Chinese role in the restoration of diplomatic relations between Saudi Arabia and Iran.

But China’s reaction to the latest violence may temporarily sour Israelis on Beijing’s advances.

In a statement Sunday, the Chinese Foreign Ministry said Israel and Palestine — it used that term instead of Hamas or Palestinians — should “remain calm, exercise restraint and immediately end the hostilities to protect civilians and avoid further deterioration of the situation.” It went on to call for a two-state solution.

For Israelis, this is infuriating. The latest attacks are arguably the worst violence they’ve experienced in 50 years. They come from a heavily armed outfit that took control of a territory after Israel had dismantled settlements there in the hopes of paving the way for long-term peace.

Israelis feel they have every right to strike back against Hamas.

Yuval Waks, a senior official at the Israeli embassy in Beijing, expressed disappointment in China’s statement. “When people are being murdered, slaughtered in the streets, this is not the time to call for a two-state solution,” Waks told reporters, according to Reuters.

That said, China is an increasingly important player in the region, and one Israel — or Saudi Arabia or Iran — is unlikely to shun any time soon.

David Cohen and Lara Seligman contributed to this report.