Professor: No end to refugee crisis without defeating ISIS 

The attacks in Paris need to be seen in context, says Robert Gerace, a retired captain in the US Naval Reserve Intelligence Program. Gerace is a professor at Rochester Institute of Technology where he has taught counterterrorism measures.

US efforts to degrade and destroy ISIS obviously haven't gone as expected, he says. You get what you tolerate, he says, and the US is tolerating the growth and expansion of the Islamic State.

"We have significantly downsized our troop strength in Iraq," he says. "Into that power vacuum, ISIS-ISIL has emerged, building an army of 20,000 to 30,000 strong. Our effort to train moderate rebels to fight in Syria has been a complete failure."

The US does not seem to have a clear strategy for defeating rather than containing ISIS, Gerace says. While the US has military aircraft and weapons systems costings millions of dollars, he says, terrorists can build an improvised explosive device for $85 and create havoc.

And given that the country is entering an election year, it will be a couple more years before a new president takes office and develops a strategy to deal with ISIS. Meanwhile, he says, Syria has lost roughly one-third of its population.

Stemming the flow of refugees is the immediate crisis facing both Europe and the US, Gerace says, but that will be difficult without resolving the root causes of the Syrian conflict and making a clear commitment to destroy ISIS.

Jens David Ohlin, a professor of law at Cornell University, says that it's important to keep in mind that the US is not at war with Islam or Muslims. Using terms like "radical Islam" doesn't help the situation, he says.

"I think specificity is the name of the game," Ohlin says. "We should be naming our enemy and our enemy here is ISIS."

Ohlin says that the only way to defeat ISIS is to engage the help of moderate Muslims in the region and through better intelligence-gathering face-to-face with people on the ground.

The last thing that the US wants to do is alienate the Muslims living in the country, Ohlin says. Tracking the activities in mosques or closing mosques would be a huge waste of time, he says.

"That's both un-American and ineffective," Ohlin says. "It's discrimination."