On Tuesday, Rick Santorum announced he was ending his quest for the 2012 Republican presidential nomination. The move comes exactly one week after Santorum lost three contests but declared the fight was only half over and that he was planning to reverse his fortunes in Pennsylvania later this month. University of Virginia Professor Larry Sabato explains what factors went into the timing of this decision and why this was actually a very smart move by Santorum. Sabato weighs in on whether this gives Newt Gingrich any chance at a final resurgence and why Romney should be happy today but his campaign coffers are even happier.