President Obama and Russian President Vladimir Putin dueled at the United Nations this week over how best to defeat the Islamic State. Much of their debate was over the role Syrian President Bashar al-Assad should – or should not – play in the fight. But when Mr. Obama chaired a summit at the United Nations Tuesday on countering the Islamic State and other forms of violent extremism, the focus was more on the community-relations building, civil society involvement, and youth outreach measures.