In a move that is raising concerns among some Vietnam War veterans, President Obama will discuss selling more U.S. arms to Hanoi during his visit to Vietnam that began Sunday night. Top White House advisers said Mr. Obama hasn’t made a decision whether to lift the partial U.S. embargo on sending military equipment to Vietnam, where more than 58,200 U.S. soldiers were killed before the fall of Saigon in 1975. But the administration sees advantages in easing the embargo, both as a warning to expansionist China and as leverage to compel the communist regime in Hanoi to improve its record...