washington defeat islamic state de facto capital raqqa may start wide struggle unite state contain insurgency launch militant group stabilize region washington grapple define comprehensive strategy syria u.s.-backed militias declare victory islamic state raqqa tuesday raise flag last jihadist footholds four-month battle sunni militant group often refer isis overrun raqqa january 2014 seize control rebel factions oppose rule syrian president bashar al-assad recapture raqqa important symbolically talk almost pyrrhic victory say bilal saab senior fellow middle east institute address economic political grievances sunnis another isis come important military fight raqqa first big city islamic state capture rapid series victories iraq syria bring millions people rule self-declared caliphate pass laws issue passports money islamic state lose much territory syria iraq year include prize possession iraqi city mosul syria force back strip euphrates valley surround desert middle east analysts say among wide array problems expose islamic state ouster raqqa find money help rebuild shatter city support fledgling local government face likely insurgency keep assad back iran russia try regain control real challenge isis turn vengeful ghost try stalk wreak havoc post-conflict security governance administration order undermine u.s. partner say nick heras center new american security u.s. state department official say washington remain commit peace process geneva support broad possible group syrian representatives discussions official say unite state ally would continue provide humanitarian assistance support efforts stabilize areas free islamic state rule include continue removal ieds explosives ... restore basic service refurbish school official say u.s. goals include support local govern body representative area civilian-led credible eye populations assad use force crush initially peaceful uprise family four-decade rule trigger country civil war 2011. conflict help create vacuum islamic state eventually fill seize part syria russia step military support assad 2015. great challenge raqqa local syrian partner try rebuild raqqa ambiguity trump administration syria policy heras say signal need send u.s. intend keep residual force areas conquer isis order oversee stabilization mission broad publicly unstated aim constrain iran ability reconquer country name assad say several analysts say unite state appear durable strategy stabilize region let alone revive moribund u.n. talk geneva aim end civil war capture lose cities say senator ben sasse republican victory underscore need comprehensive syria strategy u.s. official speak condition anonymity say russians truly want ... something really put syria back together see will return geneva process saab middle east institute suggest u.s. influence syria may slight shape events investment always always quite limit say cede terrain russia iranians almost late us get involve effectively skin game defeat islamic state raqqa may herald wide struggle u.s