Many years ago, the Israeli Bedouin expert Clinton Bailey told me a story about a Bedouin chief who discovered one day that his favorite turkey had been stolen. He called his sons together and told them: “Boys, we are in great danger now. My turkey’s been stolen. Find my turkey.” His boys just laughed and said, “Father, what do you need that turkey for?” and they ignored him.

A few weeks later the Bedouin chief’s camel was stolen. His sons went to him and said, “Father, your camel has been stolen. What should we do?” And the chief answered, “Find my turkey.”

Finally, a few weeks later his daughter was abducted, at which point he gathered his sons and told them: “It’s all because of the turkey! When they saw that they could take my turkey, we lost everything.”

I retell that story today because it’s helpful in understanding how and why we failed to contain the egregious behavior of both Donald Trump and Vladimir Putin.

They each started by — metaphorically speaking — stealing a turkey. And when we didn’t respond, they kept ratcheting up their wretched behavior to the point where Trump thinks he could shoot someone on Fifth Avenue and Putin thinks he could poison a wayward spy in London, and get away with it.

Trump’s turkey was his tax returns. During the campaign he promised to release them after the IRS finished auditing him. Then, after he was elected, Trump said, Sorry, not going to release them ever.

And nothing happened. Trump, I am reliably told, has actually said to people close to him, “Can you believe I got away with that?”

Once Trump saw that he could get away with not disclosing his tax returns, he knew he could get away with anything — sex with porn stars, endless lying, trashing the FBI, coddling Putin. Once you erase a big red line, it’s hard to start enforcing others.

Any Bedouin chief who watched the steady acceleration in the breadth and pace of Trump’s lying — like his recent boast that he had fabricated a trade deficit with Canada in talks with Canada’s prime minister or his dishonest statements to discredit Robert Mueller’s investigation — would tell you: Get me Trump’s tax returns.

Because there must be something very important in them that he wants to keep hidden. Maybe it’s just the embarrassment that he is not as rich as he claims, or, maybe, it’s something more fundamental — like how dependent he is on Russian oligarchs for financing, so much so that Putin has leverage on him. Whatever the reason, though, when Trump saw he could get away with hiding them, he knew he could break any rule, tell any lie and violate any presidential norm.

Putin’s turkey was even more serious. It was the shooting down of that Malaysian civilian airliner, Flight MH17, over Ukraine on July 17, 2014, killing all 298 people onboard.

A Dutch-led international investigation — relying on, among other things, 150,000 intercepted phone calls — found that Putin’s proxies in eastern Ukraine had requested that Russia send them an SA-11 surface-to-air missile launcher. And it was trucked over the Russian border into Ukraine, where it shot down that Malaysian airliner (probably mistaking it for a Ukrainian military plane) and then was trucked back to Russia hours later.

Who wanted to confront Russia, with all its gas exports to Europe and all its oligarchs throwing money around London or buying condos in places like … Trump Tower in New York? Putin surely also said to himself, “Can you believe I got away with that? Why not poison a former Russian spy in London with a banned military nerve agent or perpetrate genocide in Syria? Who’s going to stop me?”

Trump and Putin are cut from the same cloth. Their strategy is: keep pushing, keep grabbing, keep lying, keep denying, no matter how implausible the denials — and never apologize. Because when you lie on an industrial scale, it overwhelms everyone else. Normal people just don’t behave that way, and the sheer shamelessness eventually exhausts them.

And if we let them get away with it, your kids won’t just grow up in a different America, they’ll grow up in a different world.