Russian President Vladimir Putin did not pull the trigger, but he bears ultimate responsibility for the destruction of a Malaysian airliner and the deaths of all 298 souls on board, including 80 children.
The tragedy is a direct outcome of the mischief and violence he fomented in eastern Ukraine, where Russian-sponsored henchmen masquerading as separatists are widely believed to have fired the missile that destroyed the airliner in an apparent case of mistaken identity.
Three Ukrainian military jets have been shot down and hundreds of people killed since violence in the region escalated this spring. The risk of a major miscalculation or mishap in such circumstances was only a matter of time.
President Putin is liable for these deaths, too.
After obstructing independent investigators for several days, the so-called rebels have finally started to co-operate with international agencies, but not before they tampered with and defiled the evidence, allowing bodies to decompose for days before being moved to a refrigerated train, and removing parts of the wreckage from the crime scene.
Mr. Putin is responsible for this outrage, as well, including the depraved spectacle of drunken men roaming among the corpses and the debris.
The Russian president pretends he is merely a helpless observer, but no one is fooled, except his own people, who do not have the benefits of a free press.
The Netherlands has dispatched a prosecutor to Ukraine to collect evidence for a murder and war-crimes investigation. Nearly 200 of the victims were Dutch citizens.
The central issues in the Dutch investigation are who fired the weapon, who gave the orders and who provided the equipment?
The low-level perpetrators must be held accountable. The chain of command, however, ultimately leads to Mr. Putin, who created the conditions that made possible the shooting down of Malaysian Airlines flight MH-17.
The Russian president is unlikely to ever end up in the dock of the International Criminal Court in The Hague, even though his conduct easily qualifies him as an international outlaw.
There were high hopes in the early years of the Putin administration that he would co-operate with the world's powers in resolving the complicated issues in the Middle East, Iran, North Korea and elsewhere.
Those hopes quickly faded as Mr. Putin increasingly seemed more interested in thwarting the United States and expanding Russian influence around the world. They were dashed for good when Russia annexed Crimea in an effort to destabilize Ukraine after its pro-Russian president was deposed in favour of a pro-western administration.
It should have been clear that major sanctions were necessary, but the world responded with feeble measures, such as banning the travel of a few Russian individuals.
The European Union, which relies on Russian gas and investments, showed the least interest in punishing Russia. Germany in particular persisted in the fiction that Mr. Putin could be trusted not to escalate tensions.
America, Canada and some European nations have since announced new sanctions, but they are mostly minor inconveniences for Mr. Putin, who is motivated by much larger concerns, such as the revival of Russia as a superpower-empire.
Mr. Putin must be told to get out of Ukraine or face much stiffer measures. The timid steps so far have only encouraged him to pursue his expansionist and dangerous course of action.
Ukraine also needs much more economic assistance to help it defend itself and prevent financial collapse.
Mr. Putin has no intention of conducting his business within the bounds of international law. Left unchecked, his primitive, brutal tactics will almost certainly produce more victims.
Doing nothing, or not enough, will ultimately be more expensive than making the hard decisions today.