It is time to face facts about Russia and do something positive to help Ukraine.
President Barack Obama, German Chancellor Angela Merkel, NATO and the European Union miscalculated when they concluded that Russia would not commit aggression in Central Europe. Russia seized Crimea from Ukraine before they could react.
Western leaders also miscalculated when they assumed that economic sanctions would change Russian President Vladimir Putin’s mind about continuing aggression. Not even the cost to the Russian economy and government budget caused by plummeting oil prices has had any visible effect.
And they miscalculated when they figured that the wanton killing of 297 people aboard Malaysia Flight 17 by a Russian missile fired by Ukrainian rebels would change Mr. Putin’s approach.
They also miscalculated when they thought that Mr. Putin would respect a ceasefire between the Ukraine government and Russian-backed rebels in the industrial and mining area known as the Donbas.
Now full-scale fighting has broken out once again around Donetsk, started by newly re-equipped rebels backed by Moscow.
Clearly, Mr. Obama, Ms. Merkel and other Western heads of state have underestimated Mr. Putin, who must believe the West is too weak, too divided and too pacifist to stop him.
The stability of Europe depends on showing him that he is wrong. The tactics he has used against Ukraine could be used against NATO member nations Latvia, Lithuania and Estonia, where there are also large Russian minorities.
A first step must be taken toward re-educating the Russian president about the balance of power — and NATO resolve.
A new study by senior national security experts who have served President Obama and President Bill Clinton suggests that the White House begin by providing anti-artillery radar and anti-tank weapons to the Ukrainian army. If this step had been taken before the now-expired ceasefire, the current round of fighting might have been averted.
Now this arms supply may be the only hope of preventing the further dismemberment of Ukraine by Russia. The panel of experts, which includes former Undersecretary of Defense Michelle Flournoy, asserts that raising the military cost of the Russian invasion would support restoration of a ceasefire and political settlement.
However, Russia might simply try to overmatch the strengthened Ukrainian military and continue the fight. In that case, the U.S. and its allies should provide even more military equipment and financial support to Ukraine.
Mr. Putin will only be deterred in the long run if the U.S., Britain, France, Germany and the rest of the European Union and NATO take the necessary and difficult steps to show him that he cannot succeed at any level of confrontation with and intimidation of NATO members.