SEOUL, South Korea (AP) — As President Donald Trump seeks a nuclear deal with North Korean leader Kim Jong Un next week in Vietnam, some in Seoul are wondering if the fate of Washington's decades-long military alliance with South Korea could be at stake.

Much of this worry is linked to Trump's repeated assertions that the U.S. military deployment in South Korea is too costly, and to his surprise suspension of some U.S. military exercises with South Korea — including a major summertime drill — as a concession to Kim after their first summit in Singapore last year. Added to this concern are poli...