President Biden pumps his fist during a family photo at the NATO Summit, July 10 in Washington. Evan Vucci/Associated Press

Joe Biden’s withdrawal from the U.S. presidential race injects greater uncertainty into the world at a time when Western leaders are grappling with wars in Ukraine and Gaza, a more assertive China in Asia and the rise of the far right in Europe.

During a five-decade career in politics, Biden developed extensive personal relationships with multiple foreign leaders that none of the potential replacements on the Democratic ticket can match. After his announcement, messages of support and gratitude for his years of public service poured in from near and far.

The scope of foreign policy challenges facing the next U.S. president makes clear how consequential what happens in Washington is for the rest of the planet. Here’s a look at some of them.

ISRAEL AND THE PALESTINIANS

Biden’s strong support for Israel since Hamas’ Oct. 7 attack has its roots in his half-century of support for the country as a senator, vice president, then president.

Israeli Prime Minister Benjamin Netanyahu, an ally of former President Donald Trump who has clashed with Biden over Israel’s bombardment and siege of Gaza in recent months, did not immediately comment on Biden’s decision to drop out.

Other officials stepped up to praise Biden’s staunch defense of their country, with Israeli Defense Minister Yoav Gallant thanking Biden for his “steadfast backing” and President Isaac Herzog hailing him as a “true ally of the Jewish people.”

Before jetting off to Washington Monday — where he is set to address a joint session of Congress Wednesday — Netanyahu said that “regardless of who the American people choose as their president, Israel remains America’s indispensable and strong ally.”

With Vice President Kamala Harris being eyed as a potential replacement for Biden, Israelis scrambled to understand what her candidacy would mean for their country as it confronts increasing global isolation over its war against Hamas.

Israel’s left-wing Haaretz daily newspaper ran a story scrutinizing Harris’ reputation as Biden’s “bad cop” who has vocally admonished Israel for not doing enough to protect civilians.

“With Biden leaving, Israel has lost perhaps the last Zionist president,” said Alon Pinkas, a former Israeli consul general in New York.

Palestinians interviewed in Gaza’s central city of Deir al-Balah on Monday said it didn’t matter who became the Democratic candidate as long as Israel kept dropping U.S.-manufactured bombs on the enclave.

“We feel the United States is a partner in the assault on Gaza,” Hassan Shaqalieh said.

Experts agreed. “Both (Biden and Harris) ultimately are running on a platform and have a history of endorsing Israeli hard-line policies against Palestinians,” said Tahani Mustafa, a Palestinian analyst at the Crisis Group.

UKRAINE

Any Democratic candidate would likely continue Biden’s legacy of staunch military support for Ukraine. But frustration with the Biden administration has grown in Ukraine and Europe over the slow pace of U.S. aid and restrictions on the use of Western weapons.

“Most Europeans realize that Ukraine is increasingly going to be their burden,” said Sudha David-Wilp, director of the Berlin office of the German Marshall Fund, a research institute. “Everyone is trying to get ready for all the possible outcomes.”

Ukrainian President Volodymyr Zelensky said on X that he respected the “tough but strong decision” by Biden to drop out of the campaign, and he thanked Biden for his help “in preventing (Russian President Vladimir) Putin from occupying our country.”

Trump has promised to end Russia’s war on Ukraine in one day if he is elected — a prospect that has raised fears in Ukraine that Russia might be allowed to keep the territory it occupies.

Trump’s vice presidential pick, Ohio Sen. JD Vance, is among Congress’ most vocal opponents of U.S. aid for Ukraine and has further raised the stakes for Kyiv.

Russia, meanwhile, dismissed the importance of the race, insisting that no matter what happened, Moscow would press on in Ukraine.

“The goals of the special military operation will be achieved,” Dmitry Medvedev, deputy head of Russia’s Security council, said on the Telegram messaging app, using the Kremlin’s term for the war in Ukraine.

CHINA

In recent months, both Biden and Trump have tried to show voters who can best stand up to Beijing’s growing military strength and belligerence and protect U.S. businesses and workers from low-priced Chinese imports.

Biden has hiked tariffs on electric vehicles from China, and Trump has promised to implement tariffs of 60% on all Chinese products.

Trump’s “America First” doctrine exacerbated tensions with Beijing. But disputes with the geopolitical rival and economic colossus over wars, trade, technology and security continued into Biden’s term.

China’s official reaction to the U.S. presidential race has been careful.

“The U.S. elections are U.S. internal politics. I have no comment on this,” said Foreign Ministry spokesperson Mao Ning.

IRAN

With Iran’s proxies across the Middle East increasingly entangled in the Israel-Hamas war, the U.S. confronts a region in disarray.

Yemen’s Iran-backed Houthis struck Tel Aviv for the first time last week, prompting retaliatory Israeli strikes inside war-torn Yemen. Cross-border attacks between Lebanon’s Iran-backed Hezbollah militant group and the Israeli military have stoked fears of an all-out regional conflagration.

Hamas, which also receives support from Iran, continues to fight Israel even nine months into a war that has killed 39,000 Palestinians and displaced over 80% of Gaza’s population.

The U.S. has accused Iran of expanding its nuclear program and enriching uranium to an unprecedented 60%, near-weapons-grade levels.

After then-President Trump in 2018 withdrew from Tehran’s landmark nuclear deal with world powers, Biden sought to reverse his predecessor’s hawkish stance. But his administration has failed to renegotiate the agreement and kept severe sanctions in place.

The sudden death of Ebrahim Raisi — the supreme leader’s hard-line protege — in a helicopter crash vaulted a new reformist to the presidency in Iran. Masoud Pezeshkian has said he wants to help Iran open up to the world but has maintained a defiant tone against the U.S.

During a briefing Monday, Nasser Kanaani, spokesperson for the Iranian Foreign Ministry, brushed off Biden’s withdrawal.

“To us, the coming and going of governments and persons on top of the U.S administration is not important on its own,” he said. “What can change relations is a fundamental change in this (U.S.) hostile policy against Iran.”

EUROPE AND NATO

Many Europeans were happy to see Trump go after his years of disparaging the European Union and undermining NATO. Trump’s seemingly dismissive attitude toward European allies in last month’s presidential debate did nothing to assuage those concerns.

Biden, on the other hand, has supported close American relations with bloc leaders.

That closeness was on stark display after Biden’s decision to bow out of the race. Polish Prime Minister Donald Tusk called his choice “probably the most difficult one in your life.”

The newly installed British prime minister, Keir Starmer, said he respected Biden’s “decision based on what he believes is in the best interests of the American people.” Irish Prime Minister Simon Harris called Biden a “proud American with an Irish soul.”

The question of whether NATO can maintain its momentum in supporting Ukraine and checking the ambitions of authoritarian states hangs in the balance of this presidential election, analysts say.

“They don’t want to see Donald Trump as president. So there’s quite a bit of relief but also quite a bit of nervousness” about Biden’s decision to drop out, said Jeremy Shapiro, research director of the European Council on Foreign Relations. “Like many in the United States, but perhaps more so, they are really quite confused.”

MEXICO

The historically close relationship between Mexico and the U.S. has been marked in recent years by disagreements over commerce, the fight against cartels, energy and climate change.

Mexican President Andrés Manuel López Obrador, who took power in 2018, has cooperated with both Trump and Biden administrations to reduce illegal immigration south of the border.

López Obrador, who has boasted on many occasions about his good relationship with his “friend” Trump, said Monday that Biden’s decision to withdraw from the November presidential race is a “sovereign” one “that corresponds to U.S. authorities and leaders.”

His caution was shared by Mexico’s future president Claudia Sheinbaum, who told a news conference that Biden’s decision was his own to take and expressed to have “a lot of respect” for the U.S. president.

Associated Press writers Wafaa Shurafa in Deir al-Balah, Gaza Strip, Jill Lawless in London, Daria Litvinova in Tallinn, Estonia, Eduardo Castillo in Mexico City and Josh Goodman in Miami contributed to this report.