The shootdown of a passenger jet over Ukraine – with the loss of nearly 300 lives – is a human tragedy and a moral abomination.

Part of the outrage is that Russian President Vladimir Putin is trying to avoid culpability. His hands are bloody – or, should we say, bloodier.

Russia started this confrontation with Ukraine and armed pro-Russian separatists with surface-to-air missiles that almost certainly brought down Malaysia Airlines Flight 17. Putin and his minions can’t now disavow the horrible consequences if trigger-happy separatists mistook the Boeing 777 for a Ukrainian military plane July 17.

President Obama correctly made that point during a White House news conference.

He also rightly declared that this atrocity shows that the Ukraine crisis, which had faded from the front pages, must be resolved. “This should snap everybody’s heads to attention,” he said.

Obama is cool, calm and collected –usually good traits for the commander in chief. Still, you wish that he’d show some real emotion in times like these.

So far, European leaders, because of their closer economic ties with Russia, have been unwilling to follow the increasingly tough sanctions enacted by the U.S. Maybe the deaths of so many of their own citizens will change their minds and help increase the pressure on Putin.

“Russia can end this war,” Samantha Power, U.S. ambassador to the United Nations, told an emergency session of the U.N. Security Council. “Russia must end this war.”

To prevent more civilian casualties, that can’t come soon enough.