After more than 130 days of intense combat with Islamic State (IS) forces, Kurdish fighters, including members of Syrian Popular Protection Units (YPG) and Iraqi

pesh merga militias have largely reclaimed the city of Kobani.

The battle for Kobani began in September 2014, when IS forces started seizing villages to the east of the city. By mid-October, jihadist fighters achieved their high-water mark by claiming more than one-third of Kobani proper.

On January 26, the United States Central Command (CENTCOM) announced that Kurdish forces were in control of 90 percent of the Syrian border city, whose population swelled to over 400,000 as refugees fled toward Turkey to escape the civil war.

The U.S. aided the Kurdish fighters with over 600 airstrikes between September and January, which the YPG acknowledged played a decisive role in degrading IS’s military capabilities. The airstrikes are one aspect of Operation Inherent Resolve – America’s mission to assist ground troops against the Islamic State in Iraq and Syria.

Top American officials disagree about the importance of the victory. In October 2014, Secretary of State John Kerry denied that Kobani possessed any strategic significance. However, CENTCOM’s January 26 press release affirmed, “ISIL's failure in Kobani has denied them one of their strategic objectives.”

A defense official told Mother Jones that it was IS’s commitment to capturing Kobani that gave it its symbolic and strategic importance: "You would need to ask ISIL why the emphasis on Kobani," she said. Nearly 1,200 IS fighters died in the four-month battle.

IS’s retreat from the city comes as it has expanded its organization and operations in recent months.

In a quest to strengthen its legitimacy as the resurrected Islamic caliphate, IS has sought

bayat­ ­– a pledge of allegiance to IS leader Abu Bakr al-Baghdadi – from various jihadist organizations. In November, insurgents from five countries -- Algeria, Egypt, Libya, Saudi Arabia, and Yemen -- formally declared their loyalty to the emir.

In return, al-Baghdadi announced the creation of new wilayah – provinces – of the Islamic State, and earlier this month, an IS spokesman announced that a local leader from the Pakistani Taliban would head the Khorasan Province, which includes swaths of Pakistan and Afghanistan.

IS has also expanded its militarily in recent months, including several assaults on an Iraqi border post near Jordan.

On January 6, a female operative conducted a terror attack in Istanbul, Turkey, and on January 27, two ISIS-allied gunmen operating within the so-called Tripoli Province killed five people at a hotel in Libya, including an American security worker, former U.S. Marine David Berry.

The frequency and scope of terrorist attacks, which have occurred recently in Canada, Australia, and France, have motivated Western countries to bolster their assistance to rebel fighters and the Iraqi government.

On January 22, London hosted a summit for leaders from more than 20 countries, including Iraqi Prime Minister Haider al-Abadi, who requested more international military support while 12 new Iraqi brigades undergo training. Secretary Kerry pledged to send U.S. M16 rifles to arm the Iraqi forces, which are facing budgetary problems because of declining global oil prices.

France, which has also assisted Kurdish rebels through airstrikes in Operation Chammal, has promised to send more advisors to northern Iraq.

How to confront IS in Syria following the victory in Kobani remains a more sensitive issue, especially given the gridlock that plagues diplomatic efforts to end the Syrian civil war. IS currently controls more than 20,000 square miles of territory there, and analysts anticipate that IS is re-grouping and planning to take the town of Hasakah, which lies on a strategic location between Raqqa – the capital of the so-called Islamic State, and Mosul, Iraq’s third most populous city – currently occupied by IS.

Images have recently emerged showing the brutal enforcement of Shariah in Mosul, including crucifixions, the execution of homosexuals, and the stoning of adulterers.

The Pentagon announced on January 16 that it would send up to 1,000 troops to Syria to train moderate rebels.