It's a contest. They must compete with each other in order to win the nomination. That's what the primary is all about.
If they happen to skewer Obama while besting their opponents, all the better.
“If they happen to skewer Obama while besting their opponents, all the better.”
So far, I have seen little of this.
Instead of arguing about the best way to “bury” Obama, they are ripping each other to shreds to little end. They should be arguing tactics in correcting Obama’s mess. But the Mainstream People who run these things are steering the “debates” away from that and onto each other.