If there was unity in Syria among the many forces fighting the regime of Bashar al Assad, then the Syrian war would have been over by now, with Assad expelled from Damascus.
However, in lieu of such unity among the 1,000 plus opposition forces fighting Assad, the war continues to be executed at a costly human toll of well over a-quarter-million people slain, tens of thousands maimed and 4.8 million refugees displaced outside of Syria along with another 6.6 million internally.
Western nations rendering support to armed Syrian opposition groups have only done so at a stalemate's pace in light of the Syrian regime's big support from Russia, Iran and possible arm supplies from Belarus, North Korea and a few other nations.
Therefore, for the Syrian war to draw to a close, western nations would have to substantially increase support to the opposition. Moreover, a stronger unity would have to be crafted among the Syrian opposition to allow for an end to the war.