Dr. David Scheiner took care of Obama for 22 years. But they don't see eye-to-eye on how to fix the health care system. David Scheiner, an internist based in the Chicago neighborhood of Hyde Park, has a diverse practice of lower-income adults from the nearby housing projects mixed with famous patients like U.S. Sen. Carol Mosely Braun, the late writer Studs Terkel and, most notably, President Barack Obama. Scheiner, 71, was Obama's doctor from 1987 until he entered the White House; he vouched for the then-candidate's "excellent health" in a letter last year. He's still an enthusiastic Obama supporter, but...