Obamacare just got real. Sure, there were some new rules and benefits over the last few years, but that was just a warmup. Starting today, all of the big pieces of the Affordable Care Act ? the biggest domestic achievement of Barack Obama's presidency and one of the most far-reaching changes in American social policy in decades ? go into effect. And Americans will start to see, for better or worse, how the law really works. Private health coverage starts for more than 2 million Americans who managed to get through that federal enrollment website or the state-run versions. People with pre-existing conditions can't be turned down anymore. Subsidies will start to help low- and middle-income people pay for their insurance.