Terror threats at home and abroad took center stage Tuesday night at the lower tier Republican debate, as the four lower-polling GOP candidates jockeyed to sound the toughest message against the Islamic State.

Former Pennsylvania Sen. Rick Santorum said the best way to beat ISIS is to “take their land,” and that that should involve U.S. forces training fighters in Syria.

His comments drew a sharp rebuke from South Carolina Sen. Lindsey Graham who quipped, “You’re not going to win it that way, Rick.” He added, “There is nobody left to train.”

Graham, who served up colorful one-liners throughout the debate, said he was sick of people bashing former President George W. Bush.

 “I miss George Bush!,” he said, adding that if Bush were still in the White House, “we wouldn’t be in the mess we’re in now.”

 “I blame President Obama  for (ISIS),” Graham said. “We wouldn’t be in this mess. I’m tired of dictators walking all over us.”

Graham also said Donald Trump did not speak for all Americans when he suggested a controversial ban on Muslims. He added that declaring war on an entire religion plays into the hands of Islamic State terrorists.

“Donald Trump has done the one single thing you cannot do: declare war on Islam itself,” Graham said.

“(ISIS) would be dancing in the streets, they just don’t believe in dancing.”

The four candidates – Graham, Santorum, former Arkansas Gov. Mike Huckabee and former New York Gov. George Pataki – debated their conservative vision for the country and collectively pitched ways to defeat terror threats both at home and abroad.

Graham wants to send 10,000 U.S. troops into Iraq and 10,000 troops into Syria to fight as part of a coalition made up mostly of troops from Arab nations in the Middle East.

“There must be American boots on the ground in order to win. If you don't understand that, you're not ready to be commander-in-chief,” Graham said.

Pataki supported sending in U.S. troops but also said the U.S. should work with partners in the region, such as Saudi Arabia.

Asked how many troops he would send to the region, Huckabee said it would be a strategic mistake to announce a detailed plan on stage. He added, “We’re going to do whatever it takes.”

The debate is the fifth of the primary season, and offered candidates an opportunity to gain last-minute traction in a crowded Republican field.

The outcome of Tuesday’s debate will help shape the contest heading into the Iowa caucuses.

But some analysts say it might be too little, too late for the lower tier candidates.”

"Likely the only person who can still perhaps play an important role is Senator Lindsey Graham who is not only the senator from what will be a critical early state (South Carolina) and he could attempt to play the role of ‘kingmaker’ come February, Lara Brown, program director of the Political Management Program in the Graduate School of Political Management at The George Washington University, told FoxNews.com before the debate.

The weeks leading up to Tuesday’s debate have been challenging for candidates.

Last week, Huckabee’s longtime communication director, Alice Stewart,  called it quits. Huckabee maintains Stewart’s departure shouldn’t be seen as a sign that his 2016 bid for the White House is struggling.

However, in the latest Fox News poll in Iowa – a state where his campaign acknowledges they initially expected to do well  – the presidential contender only garnered 1 percent.  

Team Huckabee took another hit when Bob Vandr Plaats, head of the influential Iowa conservative group The Family Leader and Huckabee’s friend, endorsed rival Texas Sen. Ted Cruz.

Things also didn’t shake out well for Pataki. On Tuesday, Florida’s Secretary of State announced the candidates who would appear on the state’s March 15 primary ballot. Notably absent? Pataki.

Florida’s primary falls on the same day as other big delegate states like Ohio, Illinois and Missouri.

The Associated Press contributed to this article.