Ultimate responsibility for the massacre of the 298 people aboard Malaysian Airlines Flight MH17 begins and ends in the Kremlin office of Russian president Vladimir Putin.

Even if the triggermen who fired the missile turn out to be Donetsk locals, the so-called pro-Russian separatist militia fighters are armed and advised by Russian intelligence officers.

Until this latest outrage, Putin’s KGB-type agitation-propaganda campaign had provided timorous Europeans and Americans with enough anecdotal deceit to give his militia proxies media cover.

MH17’s fatal interception has opened eyes. For several good reasons, to include photos of SA-11 mobile launchers departing Ukraine for Russia, numerous experts believe a Russian-made SA-11 surface-to-air missile shot down MH17.

The missile itself is only one component of a complex weapon system. Militiamen do not simply find an SA-11 launcher, functional missiles, control vans, radar and other communications equipment. The Kremlin had to authorize the delivery of the SA-11 system to its militia proxies.

An ill-trained volunteer could launch the missile on a whim. However, maintaining the complex system, especially in field conditions, requires trained personnel. In order to keep the system operational, so an impulsive fool could commit mass murder, the Kremlin had to be providing essential support personnel.

The Ukrainian government has released electronic intercepts of conversations among militiamen discussing the launch. Though there is no evidence (yet) that ties a Russian field operative directly to the launch, the Kremlin initially tried to hinder international investigators. When investigators finally arrived at the crash site, they discovered that someone with a chainsaw had sliced up the plane cabin.

Will Putin and his crony government be held accountable for providing the weapon system and creating the conditions that produced this slaughter? Who holds him responsible, and how?

Verbal condemnation as a penalty for MH17 is demonstrably inadequate. Recall Putin’s Kremlin was responsible for the invasion and annexation of Crimea. The February invasion severely damaged the post-Cold War diplomatic framework for securing territorial sovereignty in Eastern Europe. Putin’s March 18 Crimean annexation completely destroyed it.

Putin was condemned, but mere words don’t deter bullies. Tough words backed by forceful actions are no sure thing, either, but they have a far better track record than sound-bite bombast.

In Crimea’s aftermath, I strongly supported the Obama administration’s call for stiff economic penalties. Russia’s economy is vulnerable to sanctions. Meaningful U.S. and European Union economic sanctions, however, have yet to be imposed. A long-term U.S.-E.U. agreement to develop alternative energy resources that reduce dependency on Russia energy exports would truly damage Putin’s regime.

I argued that economic sanctions were deserved but insufficient. Putin’s arrogant disdain for diplomatic agreements demanded a NATO political response that affirmed alliance security commitments. In March I advocated permanently stationing a reinforced U.S. heavy-armor brigade in Poland. NATO would affirm the front line. There was also an outside chance that promising to permanently station U.S. combat forces in Poland might give Putin second thoughts about waging low-level war in Eastern Ukraine.

The MH17 massacre demands a sustained American and European response to the long-term threat posed by Putin’s imperial ambitions. The objective is to create the political foundation for maintaining effective, long-term economic and diplomatic sanctions that will lead to meaningful behavioral changes and productive political changes in Russia.

The instruments for this already exist: NATO and the E.U. NATO needs to permanently station allied ground-combat units in Poland. Where and how many depend on Kremlin behavior. The E.U. must get serious about economic sanctions. This means focusing on energy alternatives to Russian supplies. The fracking revolution is about to make the U.S. a natural gas exporter. U.S. gas denies the Kremlin a potent political weapon. Unlike Russia, the U.S. is not going to threaten to shut off gas supplies to Paris, Berlin, Warsaw or, yes, Kiev. Putin has used oil and gas income to rebuild his military. Reducing that revenue hinders Russian Army modernization more effectively than a week of heavy air strikes.

Austin Bay is a syndicated columnist.