Islamabad, Feb. 18 -- In 2009, then US Vice President Joe Biden came to Munich to "press the reset button" with Russia. A decade later he came again to offer the world better relations, this time with his own country.

Promising that "America will be back" once Donald Trump leaves office, Biden won a standing ovation at the Munich Security Conference from delegates who find the president's brusque foreign policy stance hard to like.

But their elation also exposed the weakened state of Western diplomacy in the face of Trump's assertiveness, according to European diplomats and politicians who were present.

Biden's successor, Mike Pence, was met with silence at a reception in the palatial Bavarian parliament on Friday evening after he del...