A breakout moment for Cruz and Rubio, but will GOP voters respond?

For most of this year, Sen. Marco Rubio (Fla.) and Sen. Ted Cruz (Tex.) have been lurking in the background of the Republican presidential campaign. On Wednesday night, they broke out into the open, delivering strong and forceful performances in a raucous and rambling Republican debate marked by squabbling and sharp elbows.

Both Rubio and Cruz have won modest plaudits for their performances in the first two debates, but there was a demonstrable difference in what unfolded on the stage at the University of Colorado. They outshone Donald Trump and Ben Carson, the leaders in the polls, and Rubio overshadowed his onetime mentor, former Florida governor Jeb Bush.

Whether this was a unique moment for Rubio and Cruz or a foreshadowing of where the Republican nomination contest is heading is a matter of speculation, with the voters the ultimate arbiters starting early next year. But both candidates served notice Wednesday that they are ready for the next phase of a rapidly changing and increasingly fractious campaign.