Can a true conservative spend a trillion dollars on defense?
Florida Sen. Marco Rubio and Kentucky Sen. Rand Paul traded surprisingly sharp and substantive blows over the issue, with Paul accusing his colleague of being a double-talking, big government liberal in disguise.
Rubio walked into the exchange, which began in the second hour of the fourth Republican presidential debate, hosted by Fox Business Network and The Wall Street Journal.
He touted a child tax credit for families and, in quick succession, a massive boost to military spending. Paul pounced.
"You get something that looks to me not very conservative," Paul said of Rubio's plans. “How is it conservative to add a trillion dollar expenditure for the federal government that you’re not paying for?”
Rubio fired back: "I know that Rand is a committed isolationist. I'm not. I believe the world is a stronger and a better place when the U.S. is the strongest military power in the world."
Paul again: "You cannot be a conservative if you're going to keep promoting new programs that you're not going to pay for. I do not think we are any safer from bankruptcy court. As we go further and further into debt, we become less and less safe."
Paul may have had a point, but the conservative crowd cheered raucously for Rubio's line about American military power.
And the other candidates picked up on the pro-military momentum.
Texas Sen. Ted Cruz used it first and to greatest rhetorical effect. "You have to defend this country," he said. "If you think it's expensive to defend the country, see what it costs not to defend it."