In a forum on a college stage in Nashville, Tenn., Sen. Barack Obama and Sen. John McCain faced off for a second time before the television cameras, fielding questions on the economy, energy and foreign policy from an audience selected largely for its members' self-description as "undecided voters."

The discussion included plenty of policy, but will likely be more remembered for a moment when McCain pointed his finger at Obama than for anything either man said.

You said you wanted...