In a preview of what promises to be a heated race for the Republican Presidential nomination in 2016, Sen. Rand Paul (R-Kentucky) head-butted his rival Sen. Ted Cruz (R-Texas) on the floor of the United States Senate this morning. The melee came without warning, one observer said, as Sen. Paul took to the well of the Senate to give a speech recommending a strong but measured response to the crisis in Ukraine. Almost immediately, a furious and beet-red Sen. Cruz began heckling Sen. Paul, calling him a Kentucky-fried Communist and demanding that he apologize to Ronald Reagan this very instant. Sen. Paul seemed to ignore the heckling at first, but as Sen. Cruzs taunts descended into a stream of profane name-calling, the Kentuckian leapt from the well of the Senate and began throttling Sen. Cruz before administering the decisive head-butt. Shut up, you bastard! Sen. Paul reportedly shouted during the brawl. Shut up, or Ill make you shut up! A group of horrified senatorsincluding Sen. Lindsey Graham (R-S.C.), Sen. Patrick Leahy (D-Vermont), and Sen. Kelly Ayotte (R-N.H.)pulled the two men apart, aided by a C.I.A. agent who had been monitoring the Senates activities at the time. Within moments, the free-for-all was over, but not before more fists were thrown and a gash was opened over Sen. Cruzs left eye. In the aftermath of the skirmish, Sen. Paul seemed pleased with the outcome. Sen. Cruz and I may not always agree, but were both passionate about our views, he said. This kind of debate is healthy for the Republican Party. Under the rules of the Senate, head-butting another senator results in a mandatory suspension of seven days, experts said. 