British Foreign Secretary James Cleverly on Wednesday said that it was in America's best interests to keep backing Ukraine in its war with Russia, and that the U.S. was at its strongest when it when it engaged with the rest of the world. The U.K. has been at the forefront of efforts to shore up Ukraine's armed forces, training soldiers and sending arms, as it fends off the Russian invasion. But officials have privately expressed concern that a growing strand of isolationism among Republicans who back Donald Trump's America First stance could choke off aid from Washington, which has so...