The U.S. and its allies are gearing up for a military response against Syrian President Bashar al-Assad’s alleged use of large-scale chemical weapons against his own people in Syria’s ongoing civil war. Secretary of State John Kerry said the evidence chemical weapons were used is “undeniable.” But Syria’s foreign minister denies the use of chemical weapons, and says his country would defend itself using “all means available” against a Western-led strike.

On Chicago Tonight at 7:00 pm, we take a closer look at the escalating tensions with Robert Pape, political science professor at University of Chicago; Nabeel Khoury, Senior Fellow of Middle East and National Security from the Chicago Council on Global Affairs; and Ian Hurd, international law and politics professor at Northwestern University.