The bombing of Pan Am 103 over Lockerbie was premeditated mass murder. Gadhafi was taking revenge for Reagan's raid on Tripoli in 1986.

The downing of KAL 007, flying from Anchorage to Seoul, was mass murder in the second degree. Seeing an aircraft intrude into Russian air space, Soviet officers brutally ordered it shot down.

The downing of the Malaysian airliner that took the lives of 298 men, women and children was not deliberate terrorism. No one wanted to massacre those women and children.

It was a horrendous military blunder, like the U.S. shoot-down of the Iranian Airbus by the Vincennes in 1988.

That U.S. cruiser thought it was coming under attack. And Ukraine's separatists thought they were firing at an army plane.

The distinctions are as important as those between first- and second-degree murder, and manslaughter.

The respective reactions confirm this. Gadhafi concealed his role in the Scotland slaughter. Moscow was defiant in the KAL case. America was apologetic over the Iranian airliner.

Today, Vladimir Putin, with an indictment being drawn up against him, is blaming Ukraine for the war out of which the tragedy came.

But though Putin did not order the plane shot down, the horror of it all has put him in a box. And the course he pursues could determine the future of U.S.-Russian relations for his tenure.

For the rebels in Ukraine are seen as Putin's proxies. They have been armed and advised by Russia. And it was a Russian SA-11 that brought the airliner down.

While the separatists say they got the surface-to-air missiles from an army depot, there is evidence the missile was provided by Russia, and Russians may have advised or assisted in the fatal launch.

This crisis has caused President Obama to insist that Putin cut off the rebels. And if he does not rein them in, and abandon their cause, Putin is likely to face new U.S.-EU sanctions that could cripple his economy and push his country further out into the cold.

And the ostracism of Putin and the sinking of Russia's economy is what some in the West have long had in mind.

The Day of the Hawk is at hand.

John McCain and John Bolton are calling for punitive sanctions, declaring Russia an adversary, putting defensive missiles and U.S. troops in Eastern Europe, and arming Kiev.

"That's just for openers," says McCain, who wants "the harshest possible sanctions on Vladimir Putin and Russia."

"So first, give the Ukrainians weapons to defend themselves and regain their territory," McCain adds, "Second of all, move some of our troops into areas that are being threatened by Vladimir Putin."

Right. Let's get eyeball to eyeball with the Russians again.

In this "moment of moral and strategic clarity about the threat that Vladimir Putin's regime poses to world order," the Wall Street Journal said this weekend, we should send "arms to Ukraine until Mr. Putin stops arming the separatists."

The Washington Post urges "military assistance to Ukraine" and sanctions to "force Mr. Putin to choose between continued aggression in Ukraine and saving the Russian economy."

But if aiding rebels in overthrowing their government is "aggression," is that not exactly what we are doing in Syria?

Hopefully, those who prodded the U.S. to send surface-to-air missiles to the Syrian rebels are having second thoughts today.

But before we sink the Russian economy and send weapons to Ukraine, perhaps we should consider the potential consequences.

If Kiev, bolstered by U.S. weapons, decides to go in for the kill in Eastern Ukraine, Putin will face a choice: Back down and let his allies be defeated and routed, or move his army into Ukraine to protect them.

Heretofore, Putin has not done so, clearly because he does not wish to annex Luhansk and Donetsk, which would have been a cakewalk for the army he had on Ukraine's border after the Crimea crisis.

And should Ukraine, with U.S. arms, win its war in the east, what is to stop it from sending troops to recapture Crimea, which would surely cross any "red line" of Vladimir Putin.

Arming Ukraine, and putting U.S. prestige on the line for a victory by Kiev over the rebels in the east and Russians in the south, is a formula for a war Ukraine cannot win, unless the United States comes in to win it for them. Then we could be on the escalator to something unthinkable.

Sanctions on Russia can cripple her economy. But Russia can also cripple the economies of Ukraine and Europe.

Declaring Putin persona non grata may make us feel good about ourselves, but it could also mean Russia tightening ties to Beijing, and breaking up the U.S.-led sanctions regime on Iran.

Russia is on the other side in Ukraine, but in battling the Taliban and Islamic State, al-Qaida and the al-Nusra Front, she is on our side.

That "moral and strategic clarity" exists only in uncomplicated minds.

Patrick J. Buchanan needs no introduction to VDARE.COM readers; his books State of Emergency: The Third World Invasion and Conquest of America, and Suicide of a Superpower: Will America Survive to 2025? are available from Amazon.com. Patrick J. Buchanan is the author of the new book “The Greatest Comeback: How Richard Nixon Rose From Defeat to Create the New Majority.“