When President-elect Barack Obama finally makes his decision aboutwhether to proceed with deployment of U.S. missile defenses inPoland and the Czech Republic, he should know that the implicationsof that decision will reach far beyond Warsaw and Prague: It is adecision on which the future of the transatlantic security allianceitself rests. If the United States chooses to abandon its Centraland Eastern European allies as well as its obligations to NATO, itwill hand the European Union a blank check to pursue an autonomousdefense identity, independent of NATO, and will reduce America'sinfluence within the transatlantic alliance significantly.