Has Iran's success in Syria made it an arena for longer-term conflict?

Having successfully propped up the regime of Syrian President Bashar al-Assad against an array of armed rebel groups for more than six years, Iran appears to be preparing the ground for a long-term presence in the war-ravaged country, causing rising alarm in neighboring Israel, its bitter foe, and garnering the attention of Washington.Iran has spent hundreds of millions of dollars to buttress Syria’s economy, oversees a multi-national Shiite militia force to bolster Mr. Assad’s flagg