Few -- if any -- laws have divided the public like the Affordable Care Act. Ever since President Obama signed the federal health-care law four years ago this week, Republicans have pilloried it while Democrats have defended it. But why do the law's supporters like it? And why do opponents hate it? Thanks to a poll released this week by the Kaiser Family Foundation, we can answer these questions. The public remains more negative (46 percent hold an unfavorable view) than positive (38 percent hold a favorable view) toward the law, overall. That's the way it's been for much of the last four years.