The second option is to stand aside and see what Putin could accomplish with his allies. The third one, according to the Professor Emeritus of Russian Studies and Politics at NYU and Princeton, is to join Russia. Cohen sees the third option as the best choice for the Obama administration.
The main reason to support Russia in its efforts to tackle extremist groups in Syria comes down to this: the US strategy of ending the Syrian civil war has failed, while Russia's approach seems to be working at the moment.
Moreover, the Russian leader has been "absolutely candid about what he's doing" in Syria and has remained true to his word, Cohen emphasized.
Putin also sees the Damascus-led army as the only force capable of tackling radicals in Syria and this is why he is supporting Bashar al-Assad.
For its part, the US tried to create two armies to fight both Assad and the Islamic State. These initiatives had no visible effect. Nevertheless, someone has to fight Islamic State and the like on the ground.
"You need a real army to follow the bombardments and retake territory. [The US does not] have one. We are not going to send ground troops. What's the alternative to what Putin is proposing? There is none," Cohen emphasized.
The scholar also believes that Europe is increasingly viewing Russia's approach as the right one and the majority of Europeans support what Putin is doing in Syria.
"Europe now tilts politically towards Russia because of the refugee crisis driven in large part by the Syrian civil war," he noted.