Jackson Diehl of the Washington Post has come up with a reason for America to intervene in Syria: because only America can. Other nations, Diehl says, face obstacles to intervening that, happily, America doesn't face.
The problem with this argument is that the examples Diehl cites show roughly the opposite--that the downsides to intervention faced by other nations are faced by America as well.
Diehl's main example is Turkey. "Turkey cannot intervene in an Arab state without risking a broad backlash." Why? Because Turkey was a "former imperial power under the Ottomans." So that invites more Arab backlash than being viewed as a current imperial power? And a current imperial power that is allied with, as they say in the Arab world, the "Zionist entity"? I seem to recall an American intervention in an Arab state within the past decade that led to a quite sustained backlash. (Hint: The Washington Post editorial page, of which Diehl is deputy editor, strongly supported the intervention in question.)
Diehl says Turkish intervention would also face problems at a finer-grained demographic level. Turkey's "mildly Islamist Sunni government raises suspicions among Syria's large Christian and Kurdish minorities--not to mention Assad's Alawites."