MARCO RUBIO: Here's how I'd handle the military escalation between Turkey and Russia

Sen. Marco Rubio (R-Florida) argued that the US must take a hawkish response to any Russian aggression against Turkey after the country downed a Russian warplane Tuesday.

The Republican presidential candidate discussed what he would do to confront Russian President Vladimir Putin during a Fox news interview.

"Although Vladimir Putin is a gangster and a criminal, he is also geopolitical actor who makes decisions on a cost-benefit analysis," Rubio said.

Earlier in the day, Turkish fighter jets shot down a Russian warplane near the Syrian border for allegedly violating Turkish airspace and ignoring repeated warnings.

Putin responded by saying his country's plane was actually in Syrian airspace, where Russia is supposedly conducting airstrikes against the Islamic State group. Putin warned of "serious consequences" for Turkey.

But Rubio argued that the US should make clear that it would go to war to defend Turkey, which is a member of the NATO alliance. If the US did that, Rubio said he would "hope" and expect that Russia would not confront NATO.

"He'll have to do something to save face, but ultimately he is not going to test the alliance if he believes the alliance is going to stand up to him. Because he'll lose in that confrontation," Rubio said.

Rubio, who has surged to third place in a number of Republican primary polls, has focused much of his campaign on foreign-policy issues. And it's unsurprising that Rubio would use insults like "gangster" against Putin, as he has done that before. But Rubio's rhetoric highlights a divide among the Republican field.

Sen. Rand Paul (R-Kentucky), also a presidential candidate, struck a less aggressive note in his own response to the warplane incident.

"The shooting down of a Russian fighter jet illustrates precisely why we need open lines of communication with Russia and should resist calls from some presidential candidates to isolate ourselves from discussions with our adversaries," Paul said in a statement.

Paul further warned that the candidates calling for a no-fly zone over Syria - as are most Republican White House hopefuls, including Rubio - would be risking war with Russia.

"In addition, those who are calling for a no-fly zone need to realize that shooting down other countries' fighter jets will be the result and a war between nuclear superpowers a possibility," he said.

Paul and Rubio also sparred over foreign policy during the last Republican debate. Paul, a libertarian-oriented senator, backs less military intervention abroad than many of his rivals. Rubio is working to define himself as a national-security hawk.