The European Union must now do what it should have done long ago and join the United States in ratcheting up the sanctions on Russia for inflaming unrest in Ukraine. There could be some significant blowback for Europe if President Vladimir Putin moves to choke off Russian gas exports to Europe. But in the wake of the shooting down of a passenger airliner, killing 298 people, that is a sacrifice Europe must be willing to take.

Only sanctions can change the political calculus for President Putin. Until now his moves to support the separatist movement in eastern Ukraine has fed nationalistic fervor in Mother Russia and boosted the president's popularity. Combined with the message he feels his actions send to the West - don't meddle in my neighborhood - President Putin has concluded the Russian intervention in Ukraine is well worth the minor economic problems resulting from the relatively weak sanctions his nation has faced.

This is why Europe and the United States must impose far tougher sanctions and isolate Russia. President Putin will change course only if he determines the economic damage, a resulting loss in political support at home, and the erosion of his government's standing in the world community outweigh the benefits of stirring the Ukrainian pot.

Unfortunately, the forces President Putin's strategy released in eastern Ukraine will not quickly disappear even if Russia dials back support for the separatist movement. But it is a necessary first step and in time would provide the central government the ability to re-establish control.

Evidence strongly suggests Russian-backed separatists using Russian missiles shot down the Malaysia Airlines Boeing 777 on Thursday. Poorly trained and reckless, they likely mistook it for a military plane. President Putin must not interfere with the investigation, including whether any Russian personnel provided assistance prior to or during the missile firing.

For its part, Western nations should signal through backdoor diplomatic channels that they will back off from any aggressive steps to push Ukraine into the European sphere of influence if President Putin cooperates. Conversely, they must warn the Russian president of an increase in military aid to Ukraine if he does not change course.

The East-West tussle over Ukraine has unleashed dangerous forces, resulting in the deaths of hundreds of people who had nothing whatsoever to do with the conflict.