It’s not as if President-elect Barack Obama doesn’t have enough on his plate with a financial meltdown and a home-state scandal. But now he is delving into the thorny question of who can send the country into war. In between interviewing cabinet nominees and announcing health care plans, Mr. Obama plans to meet Thursday with the leaders of a commission that has proposed revamping the legal process for launching military action, to require more consultation between a president and Congress. The proposal would scrap the problematic War Powers Act of 1973, a measure passed in the hangover from Vietnam to...