In the 1972 film “The Godfather,” one of Don Vito Corelone’s oldest friends described how he conquered rival families: “You know you got to stop them at the beginning, like they should have stopped Hitler at Munich.”

When Hitler annexed a portion of Czechoslovakia in 1938, British Prime Minister Neville Chamberlain negotiated an appeasement in Munich that allowed Germany’s advance to stand.

In response, Chamberlain’s greatest critic, Winston Churchill, said: “You were given the choice between war and dishonor. You chose dishonor, and you will have war.”

A year later, Hitler’s tanks rolled across Poland and eventually all of Western Europe.

The German philosopher George Hegel said that “the only thing we learn from history is that we learn nothing from history.” Case in point: Russian President Vladimir Putin annexed Crimea in 2014, as the world watched and did nothing.

We should have “stopped Hitler at Munich.”

We should have stopped Putin at Crimea. We didn’t. We have one more chance to stop him, at Ukraine.

We must, for Putin has showed us how brutal he will be to Western Europe. His soldiers commit horrible atrocities in Ukraine, where mutilated, tortured bodies lay strewn in the streets.

In a world in which no nation puts a check on Putin, there will be no holding hands in peace. No campfire songs.

If we cut off American support — as many business and political leaders are recommending — Russia will complete its takeover of Ukraine.

There is nothing peaceful about that outcome.

We must assume that an emboldened Putin would attempt to annex Poland, a country that he considers to be part of historical Russia. That would usher in a global war, filling our media feeds with images of American soldiers fighting and dying in Eastern Europe, where we would be bound to defend our NATO allies.

Even if Putin didn’t invade Poland, his ability to do so would give him a bargaining chip in negotiations around trade and arms deals. It would limit America’s ability to control threats coming from Iran and North Korea.

A Russian victory would send a message to China that Taiwan is theirs to take. No need to worry about pushback from America.

Is that what we prefer over our current situation?

Of course not. That’s why we should reaffirm our commitment to Ukraine.

Do we see yet just how much is at stake? Can we understand how many lives will be saved by saying to Putin, “Here, and no further,” or how many will be lost if we choose the path of dishonor?

Despite our recent waffling, we can still snatch victory, but we have to define it the right way. Victory means maintaining Ukraine’s position as the world’s geographic buffer between us and Russia. Between our European allies and Putin. Between freedom and tyranny.

We don’t have to push Putin out, just keep him stuck in Eastern Ukraine, draining his resources. No American soldiers have to fight.

That strategy will work because Putin cannot support his war forever.

Russia’s defense expenditures are now 40% of its total budget. Putin has raised taxes on businesses and has begun drawing down his welfare fund to the tune of $38 billion. When that resource runs out, he will be forced to use a Stalin-era technique: forcing Russian citizens to buy war bonds.

It is a matter of time, and western industries can far out-produce Russia’s. We must now show Russia that we have the fortitude to do so.

Eventually, I pray, we and our allies will wear down Putin, and he will be forced to withdraw. We will have defeated a bully and achieved a remarkable victory for freedom and peace.

The history book our grandchildren read 50 years from now will say, “They stopped Putin at Ukraine.”