Peter Berkowitz notes that, had the Golan Heights territory won by Israel in the Six-Day War been ceded to Syria, it would most likely now be in the possession of either Hizballah or Islamic State. As for the relevant legal issues:
[First], Syria’s [current] disintegration renders title over the Golan equivocal. . . . [Moreover], international law favors stability, order, and peace; it aims to avoid resolutions that expose individuals to death or injury. Accordingly, it should prefer Israeli sovereignty over the Golan to the grim alternatives for the Golan Druze: the tyrannical rule of Shiite Islamist Iran’s puppet Assad, or the tyrannical rule of Islamic State Sunnis.
The international consensus that the Golan belongs to Syria no longer fits the facts and the law. Nor does it coincide with America’s interest in checking the spread of Islamist violence throughout the Middle East and in bolstering a democratic ally. At the first opportunity—unlikely to come before the next president’s inauguration in January 2017—the United States should affirm Israel’s lawful and just exercise of sovereignty over the Golan Heights and urge the international community, particularly U.S. allies in Europe and the Middle East, to do the same.
Read more on Real Clear Politics: http://www.realclearpolitics.com/articles/2016/02/19/why_israeli_rule_of_golan_is_lawful_--_and_wise_129706.html