Clinton's Closing Argument About 'The Heat'

In the week before the March 4 primaries (Vermont, Texas, Ohio and Rhode Island), the Clinton campaign introduced the now-infamous "red phone ad," which spoke to American fear about national security.

Now, approaching the next "must-win" contest--tomorrow's primary in Pennsylvania--her campaign debuts another fear-based spot.

On a campaign conference call just now, Geoff Garin called the ad "our closing argument in Pennsylvania."

UPDATE: Garin also called it "an entirely positive ad."