The U.S., along with a coalition of Arab nations that includes Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates, has begun airstrikes in Syria in an effort to defeat the militant group known as IS. Speaking earlier today, President Obama said the U.S. was “proud to stand shoulder-to-shoulder with these nations.” He went on to say that “There will be challenges ahead, but we’re going to do what’s necessary to take the fight to this terrorist group for the security of the country, the region and the entire world.” We’ll take a look at which countries have decided to join the U.S. and which have not, with Joseph Kéchichian, a Gulf States scholar and senior writer for the Dubai-based Gulf News. (photo: In this photo released by the U.S. Navy, the guided-missile cruiser USS Philippine Sea launches a Tomahawk cruise missile at Islamic State group positions in Syria as seen from the aircraft carrier USS George H.W. Bush on the Arabian Gulf on Tuesday, Sept. 23, 2014. (AP Photo/Eric Garst, U.S. Navy))