"I call on Congress to pass the ex-patriot terrorist act legislation I've introduced that says any American who joins ISIS to wage Jihad against Americans they forfeit their citizenship," Cruz said. "We will not allow Jihadists to come back to America using U.S. passports to murder American men and women."
"I believe we need to subject ISIS to high-profile humiliating defeat, meaning special operations attacks that are filmed basically so we can show the world that these are not invincible people," Rubio said. "It discourages people from joining their cause."
Retired neurosurgeon Ben Carson said that it is probably in order to send U.S. troops into the region to accomplish the complete elimination of ISIS through a multi-nation coalition.
"Boots on the ground would probably be important, because throughout that whole Middle East region, we have been calling for a coalition of people who have a vested interest," Carson said. "We have not seen a coalition form, but that's because there has been no leadership."
"We should be compassionate, we should use our resources and our expertise to help them get settled elsewhere," he told reporters. "There is always more that could be done."
Bobby Jindal, who said that it is a "mistake" for the U.S. to accept Syrian refugees, sent a letter to President Obama demanding more information on the refugees who will be allowed in, wanting to know what the background screening will be for each refugee and what degree of monitoring the refugees will receive once they are in the U.S.
Real estate mogul Donald Trump suggested that the carnage in Paris wouldn't have been nearly as bad if the Parisians had had guns.
"When you look at Paris, the toughest gun laws in the world, Paris, nobody had guns but the bad guys," Trump said. "But if they had guns, if our people had guns, if they were allowed to carry, it would have been a much much different situation."
"Mrs. Clinton, when the United States does not answer a purposeful terrorist attack with a purposeful and powerful response of our own and instead blames a video, then we invite more terrorism and more bloodshed," Fiorina said.
Fiorina also said she is angry that the Obama administration for its decision to accept Syrian refugees into the U.S.
Paul also dished out some criticism for rival Sen. Marco Rubio for opposing a measure he introduced a few years back that Paul says would have put greater scrutiny on people entering the U.S.
"Mine was a national security amendment and Marco blocked it," Paul said.
"Two or three years ago I introduced an amendment to the immigration bill that would have provided more scrutiny for people coming into the country, refugees, immigrants, students, they would have had background checks," Paul said. “Rubio, [Democratic Sen. Charles] Schumer and all the authors voted against any conservative amendments and I think that was a mistake not only for the bill but for our national security."
Former Pennsylvania Sen. Rick Santorum suggested that Obama is "in alternative world" when it comes to understanding the threat posed to radical Islam and prescribed "launching a major offensive against ISIS" to bomb ISIS back into the seventh century.