Republican presidential candidates are introduced to the audience at the South Carolina Presidential Debate at Wofford College.

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GOP presidential candidates discuss national security issues in South Carolina debate

Texas Gov. Rick Perry moves past earlier debate gaffe, touts new foreign aid proposal

Michele Bachmann's campaign upset with CBS political director

Spartanburg, South Carolina CNN  — 

The Republican candidates for president tackled national security issues on Saturday in a 90-minute debate in South Carolina. Moderators steered the eight candidates toward terrorism, Iran, China, the war in Afghanistan, the Arab Spring and foreign aid.

National security has largely taken a backseat to the economy and domestic issues. Here are five things we learned on Saturday:

Perry survives

Humor was injected into the policy-focused debate thanks to Texas Gov. Rick Perry, who joked about the embarrassing mental lapse that came to define his campaign earlier this week in a debate in Michigan.

The gaffe came up when Perry was asked about the Energy Department by CBS News moderator Scott Pelley.

“Glad you remembered it,” Perry quipped about the agency he wants to eliminate, even though it had awkwardly escaped his memory in Michigan.

“I have had some time to think about it sir,” Pelley replied.

“Me too,” Perry said, eliciting laughter from the crowd.

Perry answered several questions with confidence. He drove the discussion on foreign aid commitments when he said he would zero out all foreign aid and start again from scratch, including close ally Israel.

GOP candidates tackle foreign policy, national security in debate

Plus, he stole the show when he made a discussion about waterboarding personal, highlighting his military service and his commitment to protecting men and women in combat.

“For us not to have the ability to try to extract information from them to save our young people’s live is a travesty,” Perry said. “This is war, that’s what happens in war, and I am for using techniques – not torture – but using those techniques that we know will extract information to save young American lives.”

Zero, not nine

Sorry, Herman Cain: The operative number in Saturday’s debate was not 9, 9 or 9. It was zero.

Perry said that’s the amount of foreign aid every country in the world would receive at the outset of his administration. Each nation would then have to explain why they deserve American funds – even Israel. Perry later clarified that Israel, a staunch ally, would continue to receive “substantial” money from Washington.

The proposal was a warning shot to Pakistan, which continues to receive billions of dollars in aid from the United States even though its intelligence services have been linked to terrorists.

Several of the candidates seemed to agree with Perry, even former Massachusetts Gov. Mitt Romney, who said aid to Pakistan should be zeroed out and re-evaluated. And so, not only did Perry escape Spartanburg without another embarrassing gaffe on his hands, he actually made news with a policy proposal.

CNN Truth Squad: Fact checking the GOP debate

Cain read his briefing book

Cain, the former pizza executive with scant foreign policy credentials, might have had the most to prove tonight in a debate about the rest of the world. Admittedly, the bar was exceedingly low.

After all, Cain has repeatedly waded into gaffe territory when asked for his foreign policy views and seems to revel in his lack of knowledge about the world. (See: “Ubeki-beki-beki-beki-stan-stan”).

Still, the pressure was on when he was asked the first question of the debate, one about Iran pursuing a nuclear weapon and what he would do about it.

But Cain clearly read his briefing book and hit the right points, even though he definitely appeared nervous wading into territory outside his catchy “9-9-9” comfort zone. But in the end, there were no major blunders for the man who seemed not to know a few weeks ago that China has nuclear weapons.

That’s a win for Cain.

When in doubt, attack the media

Cain has made attacking the media a central plank of his candidacy in the wake of a series of sexual harassment allegations.

Minnesota Rep. Michele Bachmann was handed an opportunity to take a similar path on Saturday when CBS Political Director John Dickerson accidentally copied a Bachmann aide on an email saying that the candidate was largely irrelevant and would not be asked many questions in the debate.

The Bachmann campaign called on Dickerson to be fired and accused the network of sidelining a candidate based on her diminished standing in the polls.

Bachmann’s campaign manager stormed through the post-debate spin room and called Dickerson a “piece of sh-t” and a “fraud.” Dickerson’s response: “Bachmann is at 4% in the polls and has been for a while. Other candidates aren’t. I sent an email based on that.”

Bachmann wasn’t the only one complaining: Jesse Benton, a senior adviser to Texas Rep. Ron Paul, called the debate a “disgrace” and said his boss was limited to just a few minutes of debate time.

Cain has impressively maintained a steady position atop of the Republican polls during his scandal, a sign that the age-old strategy of attacking the press is a great way to gain a foothold in a party that has long viewed the “mainstream media” with suspicion. Bachmann and Paul might score some points by doing the same.

Romney still steady

Improbably, after 10 presidential debates – or is it 11? - the putative GOP frontrunner survived unscathed once again. His rivals, particularly Perry and former Utah Gov. Jon Huntsman, will almost certainly pick apart his answers on the foreign policy front.

But Romney has yet to suffer the kind of campaign-altering blunder that these nationally televised debates tend to produce. And this is in a presidential campaign that has been almost entirely defined by the marathon debate schedule.

It’s not luck, exactly, because Romney has shown himself to be a skilled campaigner after having run a national campaign once before.

But if you find yourself in Iowa, it might not be a bad idea to get him to buy you a lottery ticket if you spot him at the local Kum N’ Go.

CNN’s Shawna Shepherd contributed to this report.