Last year, President Barack Obama said that if Syria's Assad regime used chemical weapons it would be a "red line
" for his administration. Now Obama is pushing for a military response to punish Assad for crossing that red line. Ultimatums are nothing new in diplomacy and warfare. To take a look at what we can learn from some 'red lines' from our ancient and recent past, Day 6 is joined by Dan Carlin
, host of the podcasts Hardcore History
and Common Sense
. Dan will be a regular guest in coming months, joining Day 6 from time to time to look at the news of today through the lens of history in a segment we're calling "The Long View".