Democrats are fretting that Obamacare is going to crush their hopes of big gains in the midterm elections, just like it cost them the House in 2010. And as bad-news headlines and big-time dips in the polls pile up, the signs of anxiety are starting to show. On Monday night, South Carolina’s Elizabeth Colbert Busch, a favorite of the Democratic left, couldn't get away from the law fast enough, calling Obamacare “extremely problematic” — a quote that got wide play from GOP groups like the National Republican Senatorial Committee. Sen. Max Baucus warned that there could be a “train wreck”...