The downing of a Malaysian Airline plane over Ukraine will mean a cold relation between Russia and the U.S. for years to come. I think it is obvious that Ukraine rebels fired the missile, mistaking the plane for an Ukrainian air force jet. But the sophisticated weapon can only be supplied by Russia. Putin will lie and try to cover this up but nobody from the western world will believe him. The U.S. had announced tougher sanctions days before this and will tighten the grip on Russia more now. More importantly, the Europeans, who had not been as tough on Russia because of their larger trades with Russia, is now much more outraged. So I believe the Russian economy, which had been slowed lately, may well going into a recession.
While we can use Russian help in Syria, Iran and North Korea, they have not been much help anyway. Putin will hang on power because of propaganda about Ukraine have increased nationalism in his favor. But eventually the economic blows will make it hard for him to stay in power. This may take a few years but we must be patient. After all there is no military solution to this.