WASHINGTON—Ukraine President Volodymyr Zelensky told lawmakers his top priority is securing U.S. permission to fire long-range missiles to hit military targets in Russia, as he held a whirlwind set of meetings at the White House and Capitol laying out his plan to turn the tide in the war. The visit provided a forum for Zelensky to thank the U.S. for its continued support and to try to smooth over tensions with Republicans ahead of the November elections, whose outcome could...