Jon Cohn explains today that although most of Obamacare doesn't take effect until 2014, parts of it are already working:
For the first time in three years, the proportion of Americans with health insurance rose, from 83.7 percent in 2010 to 84.3 percent in 2011.
And what explains the shift? The breakdown by age offers some clues. Relative to last year, the percentage of young adults with health insurance rose by 2.2 percent. That was the largest increase of any group. And it was the second year in a row that coverage among young adults increased....As you probably know, the Affordable Care Act allows young adults to enroll on their parents' health insurance plans if they have no access to coverage on their own. That provision surely doesn't account for all of the young adults getting coverage. But it almost certainly explains a lot of it.
Good job, Obamacare! I'll note in passing that this particular provision of Obamacare is quite popular with the public, so naturally it's one of the provisions that Mitt Romney says he'd keep. He just won't explain how. But I'll give him a hint: the free market declined to allow young adults to enroll on their parents' policies for 80 years before the passage of Obamacare. If Romney really likes this idea, it's going to take something more than the free market to keep it around.