WASHINGTON — China has now assumed the mantle of fighting climate change, a global crusade that the United States once led. Russia has taken over Syrian peace talks, also once the purview of the American administration, whose officials Moscow recently deigned to invite to negotiations only as observers.

France and Germany are often now the countries that fellow members of NATO look to, after President Donald Trump wavered on how supportive his administration would be toward the alliance.

In the Israeli-Palestinian conflict, the U.S., once the only mediator all sides would accept, has found itself isolated after Trump’s decision to declare that the U.S. recognized Jerusalem as the capital of Israel.

In his wide-ranging speech on national security last week, Trump highlighted what he called the broadening of U.S. influence throughout the world.

But one year into his presidency, many international leaders, diplomats and foreign policy experts argue that he has reduced U.S. influence or altered it in ways that are less constructive. On a range of policy issues, Trump has taken positions that disqualified the United States from the debate or rendered it irrelevant, these critics say.

Even in countries that have earned Trump’s praise, like India, there is concern about Trump’s unpredictability — will he be a reliable partner?

“The president can and does turn things inside out,” said Manoj Joshi, a scholar at a New Delhi think tank, the Observer Research Foundation. “So the chances that the U.S. works along a coherent and credible national security strategy are not very high.”

As the U.S. recedes, other powers like China, Russia and Iran are eagerly stepping into the void.

Significant are the visible gaps between the president and many of his top national security advisers.

Trump’s speech was intended to explain to the public a 70-page strategy document that the administration developed.

But on key issues, Trump’s speech and the document diverged. The speech, for example, included favorable rhetoric about Russia and China. The strategy document listed the two governments as competitors, accused the Russians of using “subversion” as a tactic and said that countering both rival powers was necessary.

At the same time, Trump’s refusal to overtly criticize Russia, some diplomats say, has emboldened President Vladimir Putin in his military actions in Ukraine. Kurt Volker, the administration’s special envoy for Ukraine, said last week that some of the worst fighting since February took place over the past two weeks. Volker accused Russia of “massive” ceasefire violations.

Nicholas Burns, who served as a senior American diplomat under Republican and Democratic administrations, said the administration’s strategy was riddled with contradictions that have left the U.S. ineffective.

Trump “needs a strong State Department to implement” its strategy, he said. “Instead, State and the Foreign Service are being weakened and often sidelined.”

Trump’s “policy of the last 12 months is a radical departure from every president since WWII,” Burns said in an interview. “Trump is weak on NATO, Russia, trade, climate, diplomacy. The U.S. is declining as a global leader.”

The most recent example of U.S. isolation came with Trump’s decision to formally recognize Jerusalem as the capital of Israel, delighting many Israelis, but angering Palestinians and reversing decades of international consensus.

“From now on, it is out of the question for a biased United States to be a mediator between Israel and Palestine,” Turkish President Recep Tayyip Erdogan said at a summit of more than 50 Muslim countries in Istanbul.

Regional leaders and analysts say for all of Trump’s rhetoric, they see few concrete steps by the U.S. to counter Iran’s expansion of its military, economic and political influence, a perception Tehran is happy to exploit.

“Trump is ranting and making empty threats,” said Hamid Reza Taraghi, a conservative Iranian politician with close ties to Iran’s supreme leader. “Russia, China and Iran are gaining ground in the Middle East, and America is losing ground and influence.”

That view is also shared by Iranian moderates, with whom the Obama administration thought it could work.

In Syria and Iraq, the U.S. under Trump has succeeded in helping its allies drive Islamic State militants out of their strongholds.

But Washington has opted to take a back seat in the other conflicts roiling the two countries. Another round of U.N.-mediated and U.S.-backed peace talks on Syria has wrapped up without any progress. Instead, a Russia-led process is gaining traction.

Trump has won praise in parts of South Asia, a region his team has re-dubbed the “Indo-Pacific” and where it is favoring India and Afghanistan over Pakistan. The administration has asked Congress for $350 million in aid to Pakistan for 2018, not quite one-tenth the amount Washington provided five years ago.

Afghan officials are encouraged by Trump’s renewed pressure on Pakistan to stop militant groups operating from its soil.

But even there, officials say they worry Trump’s rhetoric will strengthen China’s status as a power broker.

Staffers Zavis and Bengali reported from Beirut and Mumbai, respectively. Special correspondents Ramin Mostaghim reported from Tehran; Omar Medhat from Cairo; and Samir Zedan from Bethlehem, West Bank.

tracy.wilkinson@latimes.com