1.   After years of research and investment, the United States has yet to produce a defense that can shoot down a single warhead.

2.   Right now, Western analysts say, China may have no more than two dozen long-range missiles, capable of reaching parts of the United States with single warheads.

3.   To date, targets in the interception tests have consisted of a single mock warhead and a single decoy balloon.

4.   To maintain nuclear equality with the United States, Russia might feel compelled to initiate an expensive program of building single warhead missiles.

5.   To get back to parity, Russia would have to build a number of single warhead missiles, such as the Tridents, something it is loathe to do.

6.   Under START I, for instance, a bomber was counted as a single warhead even though it carried more.

7.   He also has suggested that Moscow could respond to U.S. moves by fitting multiple warheads to its single warhead missiles.

8.   It can only afford to build a few new missiles, but START II means they must be fitted with a single warhead.

9.   Neither would be required to destroy a single warhead, a senior administration official told reporters at the White House.

10.   Putin has said Russia might respond to the U.S. moves by fitting its single warhead missiles with multiple warheads in order to overwhelm the defense system.