Is There Such a Thing As a Just War? Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email Pope Francis waves from the Popemobile on his way to attend the Via Crucis on Copacabana Beach during World Youth Day celebrations on July 26, 2013 in Rio de Janeiro, Brazil. ( Buda Mendes / Getty ) Produced by PRI and WNYC