CNN Opinion asked a range of contributors for their take on last week’s attacks in Paris and how the war on ISIS must change if the U.S. and its allies want to defeat it. The opinions expressed in these commentaries are solely those of the authors.

Fareed Zakaria: What does ISIS want?
The barbarism of the attacks in Paris mark a new low in terror. The attacks were not directed against national symbols or government targets, but designed simply to kill innocent men, women and children. The murderers did not even bother to issue demands.
French President Francois Hollande has called Friday’s attacks an act of war. They were worse. War has a goal. It’s fought by soldiers against soldiers. This is nihilism — violence as an end in and of itself.
That doesn’t, however, answer the question what to do. In the wake of the attacks, people rightly ask, what could France have done better? What could the United States have done better? And people are offering up various solutions regarding borders, visas, police procedures and the battle against ISIS in Iraq and Syria.
Would this really have prevented this kind of attacks?