Another falling dictator might soon make a splash in the oil market.The latest domino set to drop in the Middle East appears to be Bashar Assad of Syria. U.S. Director of National Intelligence James Clapper said Tuesday that he thinks it's only "a question of time" before Assad joins Muammar Gaddafi, Hosni Mubarak and others on the scrap heap.Assad's fall could push other regimes to wobble and possibly foment more turmoil elsewhere in the Middle East, and that could roil an already choppy crude-oil market.