User blog comment:Dmurray1031/Whitebeard vs. Shanks (both full strength)/@comment-174.51.125.171-20121019070325/@comment-39.53.69.9-20141012102201

Sengoku only agreed to stop the war because of the damage Whitebeard pirates had already done. The Marines didn't had enough strength left to fight another of the yonko.