If oil is an obstacle in getting U.S. allies to cooperate on Libya, it may help win the release oftwo Americans being held prisoner in Iraq. Clinton Administration officials said they are asking France, Russia and Turkey to help intercede with Saddam Hussein's government. Though all three nations opposed Iraq in the Gulf War, they are now eager to end U.N. sanctions against Iraq and renew oil trading. (Turkey claims the sanctions have cost its economy $20 billion.) This afternoon in Washington, an impatient Senate passed an unanimous resolution urging President Clinton to "take all appropriate action" to assure the Americans' release, reflecting an inclination by some senators to threaten military action. Said Senate Majority Leader Bob Dole: "Diplomacy is certainly what we should start with."