Ted Cruz is wilting under fierce attacks from Marco Rubio.

An hour into the fifth Republican debate, Rubio was already piling onto Cruz, who surpassed Donald Trump to claim first place in Iowa polls this week. With national security taking on added significance in the days after the San Bernardino shooting, Rubio skewered the Texas senator for voting to limit the collection of metadata.

“Marco knows what he’s saying is not true,” Cruz said.

“I don’t think national television in front of 15 million people is the place to discuss classified information,” Rubio replied. “So let me just be very clear. There is nothing that we are allowed to do under this bill that we could not do before.”

Twenty minutes later, they exchanged fire once again, with Rubio turning on Cruz for failing to support the Defense Authorization Act. “Three times he voted against the Defense Authorization Act,” Rubio said. “We are going to be left with the oldest and smallest air force this country has ever had.”

“Marco has continued these attacks. He has cast more than a few insults in this direction,” Cruz replied, ashen faced. “ISIS and radical Islamic terrorism will face no more a determined foe than I am.”

What we are seeing on stage could be a preview of the coming months.