In the following video, Dan Caplinger, The Motley Fool's director of investment planning, reviews the various lawsuits that people have filed challenging aspects of the Affordable Care Act. Dan notes that the wide variety of different theories presents a formidable attack against Obamacare and he runs through the various suits pending. He concludes with a look at the investing ramifications, pointing out that for insurer UnitedHealth Group ( UNH -0.22% ) and hospital companies HCA Holdings ( HCA 0.88% ) and Community Health ( CYH 4.46% ), the uncertainty involved could reverse their impressive share-price gains recently.