In taking up President Barack Obama's health overhaul Monday, the Supreme Court wades into an issue that not only could sway this fall's elections but also could help define for generations what Congress is and isn't entitled to do.
To win, the challengers must secure all five conservatives. Based on his prior opinions, Justice Clarence Thomas seems virtually certain to vote against the mandate. The records of the other four, however, are sufficiently ambiguous as to make their votes more difficult to predict. Of the justices considered persuadable, Justice Anthony Kennedy may be the biggest target, as his opinions were cited in the two sides' briefs far more than those of any other justice.
The court also could punt. One federal appeals court, the Fourth Circuit, in Richmond, Va., ruled that a challenge can only take place in 2014 or after, when those penalized under the law's insurance mandate actually have to pay their penalties.