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 North Atlantic alliance.

And 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 recognize Jerusalem as the capital of Israel.

In his 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, such as India, there is concern about Trump's unpredictability — will he be a reliable partner? — and what many overseas view as his isolationism.

"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."

One significant issue is the visible gap between the president and many of his top national security advisers.

Trump's national security 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 generally 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.

Russia reacted angrily: America continues to evince "its aversion to a multipolar world," said President Vladimir Putin's spokesman, Dmitri Peskov.

At the same time, Trump's refusal to overtly criticize Russia, some diplomats say, has emboldened Putin in his military actions in Ukraine, where Russian-backed rebels are battling a pro-West government in Kiev.

Nicholas Burns, who served as a senior 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."