Yep he is. And you need loose cannons to win wars. We are at war. We won't win it with Rickie Squirt gun or Mitt "ready, aim, AIM BUT NEVER ACTUALLY FIRE!" Romney.
We need someone who will fire and fire and fire. And yes, there will be collateral damage from time to time. Welcome to war. But with Newt, there will be many many many more direct hits on the target than with anyone else running. And even in this situation, he scored several direct hits.
Be careful with your cliches. They might come back to bite you.
Loose cannons also fire at friends.