The United States will forge ahead with plans for a missile defense system in Eastern Europe even if efforts to calm Russian opposition fail and officials cannot agree on a joint program, a senior Pentagon leader said Tuesday. Eric Edelman, undersecretary of defense for policy, said the United States and Russia have been discussing several ways to cooperate on the plans, which would put a radar system in the Czech Republic and about 10 missile interceptors in Poland. The system would be used to guard against potential attacks against the United States and Europe from countries such as Iran. Edelman said if the talks should fail the United States would not allow Russia "to dictate what we do bilaterally with other countries." "We want to cooperate with Russia," said Edelman, who recently returned from meetings in Europe about the plan. "We think the threat is one that they face as well as one that we face. In fact, they come within range of these missiles before we do."