Whatever its ultimate ruling in June may be, the US Supreme Court made history this week. It's taken two years for the Affordable Care Act to reach the Court, which is lightening speed by normal standards. After three days of arguments, the fate of President Obama's most important legislative achievement is very much up in the air. Will the Supreme Court throw out the "mandate" to buy insurance? What about requirements already in effect, like insurance despite pre-existing conditions? What's the potential impact on this year's presidential election?