Sen. Rand Paul on Tuesday deployed himself as a battering ram against Establishment darlings Marco Rubio and Jeb Bush and a potential favorite, Carly Fiorina, confronting and undercutting their arguments more aggressively and effectively than any of the leading “outsiders” in the race.

Paul did the most damage to Rubio, repeatedly questioning his conservatism during one of the most heated exchanges of the night’s GOP debate on Fox Business News.

Though Rubio countered well, Paul weakened any claim Rubio might make on the base, slamming his plans to provide a new child tax credit, which Paul described as effectively an expenditure, and increase U.S. involvement overseas.

Rubio opened himself up to Paul’s criticism by touting the credit.

“And so, yes, I have a child tax credit increase, and I’m proud of it. I am proud that I have a pro-family tax code, because the pro- family tax plan I have will strengthen the most important institution in the — in the country, the family,” Rubio said.

Paul described the credit as a federal expenditure masquerading as a tax cut, saying it failed to pass the conservative smell test.

“We have to decide what is conservative and what isn’t conservative,” Paul declared. “Is it fiscally conservative to have a trillion-dollar expenditure? We’re not talking about giving people back their tax money. He’s talking about giving people money they didn’t pay. It’s a welfare transfer payment. Is it conservative to have … a new welfare program that’s a refundable tax credit?”

Rubio said the credit could be used by people to offset their Social Security taxes. But then, presumably, the money owed to Social Security would have to come from somewhere else.

Paul then dug into Rubio’s military spending plans.

“Add that to Marco’s plan for $1 trillion in new military spending, and you get something that looks, to me, not very conservative. Thank you,” Paul said.

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

Rubio turned the tables a bit, calling Paul a “committed isolationist.” But by then, the damage was done.

Later, when Bush and Fiorina sought to sound tough by advocating a no-fly zone over Syria, Paul called out the thoughtlessness underpinning their instinct for interventionism.

“We have to lead, we have to be involved. We should have a no fly zone in Syria,” said Bush, a former governor of Florida.

“We must have a no-fly zone in Syria because Russia cannot tell the United States of America where and when to fly our planes,” said Fiorina, the former CEO of Hewlett-Packard.

Well, just one problem with that, Paul noted. If you want to create an empty sky where Russian planes are operating, you’re going to have to remove them — by force.

“Russia flies in that zone at the invitation of Iraq. I’m not saying it’s a good thing, but you better know at least what we’re getting into,” Paul said. “So, when you think it’s going to be a good idea to have a no fly zone over Iraq, realize that means you are saying we are going to shoot down Russian planes.”

Paul’s final remarks included yet another claim to the conservative mantle and an implicit criticism of the Establishment candidates’ failure to “conserve all the money” taxpayers entrust them with.

“We have to be conservative with all spending,” whether for the military or domestically, Paul said. “I’m the only fiscal conservative on the stage.”

[lz_apester id=”56411ae73eaa7f1434ecd2b7″ height=”674″]