How to prevent another Paris? Experts debate issues that divide, unite

Should we be optimistic or pessimistic about whether attacks like the one in Paris can be prevented in the future? CNN hosted an email discussion featuring Brookings fellow Shadi Hamid, former CIA analyst Cindy Storer, Texas A&M associate professor Sahar Aziz and New America Foundation research fellow Barak Barfi about the integration of Muslims into European society and whether French law enforcement authorities dropped the ball. Their comments have been edited for clarity and style. The views expressed are their own.