Ted Cruz has jumped into the lead in Iowa, according to a new poll from Monmouth University. While this is the first poll Cruz has led, it has been somewhat expected given his climb in recent weeks. Much of Cruz's support growth can probably be traced to a corresponding fall by Ben Carson. 

The image at left shows that Cruz has more than doubled his support since late October's Monmouth poll, as Carson has lost more than half of his. While this transition from Carson to Cruz was happening, Donald Trump took the lead in other Iowa polls and he maintains a small lead in our 5-poll Iowa average. Marco Rubio has also seen significant growth in support, and is just behind Trump in this latest poll.