The SDF are aiming to defend themselves against the Islamic Republic of Turkey: http://www.thedrive.com/the-war-zone/17818/turkey-launched-an-offensive-against-kurds-in-northwestern-syria-heres-why-it-matters
Here, if you are interested, is a piece I wrote in January 2015 on the Battle of Kobani: https://quadrant.org.au/magazine/2015/01-02/battle-modernity-borders-kurdistan/
