The deliberate downing of Malaysia Airlines Flight 17 should not be compartmentalized in East-West, post-Cold War geopolitics. It was a crime of mass murder, and we join the global mourning for the loss of innocent passengers.

While the lives of all 298 on board were precious, it’s especially tragic that among those killed were many who had dedicated their professional lives to saving lives through AIDS research.

Their humanitarian work contrasts with the cowardly selfishness of those accused of firing on the jet — Russian-leaning Ukrainian separatists, many of whom received direct support from Russia.

Evidence of the connection continues to mount. On Sunday, Secretary of State John Kerry said that U.S. intelligence agencies tracked the launch of a missile from a rebel-held area in Eastern Ukraine. And the U.S. embassy in Ukraine’s capital, Kiev, also confirmed the authenticity of recorded conversations in which rebel leaders boasted about their barbaric act.

Compounding this cruel disgrace, separatists initially blocked access to the crash site, withheld the recovered “black boxes” from the Ukrainian government and, in a particularly despicable insult to victims’ families, held hostage the corpses of victims.

Facing intensifying international pressure, the rebels eventually yielded on Monday and reluctantly cooperated with investigators. Separately, Russian President Vladimir Putin called for access to the crash site and said no one has a right “to use this tragedy to achieve their narrowly selfish political goals.”

Even by Putin’s low standards, such a statement is highly hypocritical. His government has encouraged, trained and armed many of the separatists. The destabilization has led to a low-level war that has killed scores in Ukraine. And although many in the West unfortunately seem to have forgotten, Russia annexed Crimea in clear violation of international law.

Europe, and the world, should fear that Putin’s ambitions are bigger.

“Mr. Putin has established a doctrine that he can protect ethnic Russians and Russian speakers wherever they may be — and there are a lot of them in Estonia, Latvia, Lithuania, Bulgaria, Romania and Poland, and a whole lot in Kazakhstan,” said John Herbst, former U.S. ambassador to Ukraine and now director of the Atlantic Council’s Eurasia Center. “This is a challenge to all of those countries. So the games being motivated by short-term economic interests are fool’s games, because if Putin wins in Eastern Ukraine he’s not going to stop.”

To date, European leaders have been reluctant to impose meaningful economic sanctions on Russia. Although tougher measures were taken at Tuesday’s meeting of European Union (E.U.) foreign ministers, they were nowhere near “sector” (or targeted) sanctions that could significantly restrict Russia’s economy.

While a transparent investigation into the crash of Flight 17 is warranted, Russian aggression before and even since then gives Europe ample reason to act.

This week’s tough talk from British Prime Minister David Cameron was encouraging, but it was overshadowed by the news that French President Francois Hollande would proceed with the sale of the first of two Mistral helicopter carrier warships to Putin’s Russia. The second delivery, Hollande said, would depend on “Russia’s attitude.”

Russia’s attitude — Putin’s really, since he leads like a democratically elected dictator — appears quite clear. For instance, he has used Russia’s perch as a permanent member of the United Nations Security Council to protect Syria’s homicidal regime. He has destabilized neighboring nations like Georgia and earlier this year annexed Crimea.

Ukraine relinquished its vast arsenal of nuclear weapons at the end of the Cold War in exchange for guarantees of territorial sovereignty. Russia’s annexation of Crimea and the war against Ukraine send all the wrong signals to Tehran as world powers try to convince Iran to abandon its potential nuclear weapons program.

The attack on the Malaysian jet should be a long-overdue turning point for the West when it comes to responding to Russia. After years of post-Soviet engagement and enticements for the country to become a productive international actor, and recent half-measures to deter further incitements, a strategic shift is needed.

It’s time for the West to wake up to Putin, who considers the dissolution of the Soviet Union the “greatest geopolitical catastrophe of the century.” In reality, the breakup meant freedom for millions who suffered under Soviet domination. The West must make it unmistakably clear that Putin’s provocations will be met with extraordinarily high economic and political costs. Although such a response could hurt already-shaky European economies, much greater economic damage would occur if Putin is left unchecked.

Stricter sanctions should be imposed to make Putin, ever the KGB officer, refigure his Cold-War calculus. He needs to realize that he’s weakening Russia — and his own hold on power — by menacing neighboring nations.