North Korea dashes hopes of quick progress on nuclear standoff after historic concert

Less than a week after a soaring symphony raised hopes of detente on the Korean peninsula, North Korea leveled a new tirade Monday against the U.S. military presence in South Korea, dashing expectations of quick progress in its nuclear standoff.

In a further setback, the main U.S. negotiator in the long-running arms talks with Pyongyang headed home Monday having failed to win a meeting with his North Korean counterpart after lingering in the region following the New York Philharmonic's historic performance in Pyongyang last Tuesday.

U.S. officials had warned the good will generated by the emotional concert would be meaningless without North Korea fulfilling …