In the wake of President Obama’s decision to scrap the U.S. missile defence shield in eastern Europe, many are pondering Russia’s response. The relationship will remain in the spotlight this week, when President Medvedev heads to the U.S. for the G20 summit. Although the precise nature of Russia’s reaction remains to be seen, it has a big incentive to improve relations. It badly needs American investment and co-operation to help solve serious economic problems at home.