North Korean leader Kim Jong Un, center, smiles as he...

North Korean leader Kim Jong Un, center, smiles as he and Chinese counterpart Xi Jingping, left, attend a banquet in Beijing last week. Credit: AP

It’s a common lament that politics don’t stop at the water’s edge. Foreign policy, the argument goes, should be run on the basis of national interest, not party politics. But in reality, U.S. administrations of all colors have a lot of beliefs in common. Unfortunately, all too often, they believe in illusions.

Today’s best example is President Donald Trump’s not-yet-scheduled summit with North Korean dictator Kim Jong Un. Of course, I hope Trump’s initiative succeeds. If he achieves a genuine denuclearization of North Korea, without conditions, he deserves the Nobel Peace Prize.

But other administrations believed the North would negotiate away its nuclear weapons program. All were wrong. The Clinton administration had the Agreed Framework of 1994. The George W. Bush administration negotiated desperately after 2006. Neither succeeded.

It’s unlikely North Korea has changed its stripes. It’s spent a lot of money on its nuclear program, so it wants the bomb badly. It also wants U.S. forces out of South Korea. In short, the summit feels like a trap — like our other hopeful parlays with the Hermit Kingdom.

Or take Russia. For years after the Cold War, U.S. policy toward Russia was premised on the belief that Russia was on a bumpy road to democracy. Administrations from those of George H. W. Bush to Bill Clinton to Bush to Barack Obama proceeded on this basis.

When Russia went bankrupt, we bailed it out. When Russian oligarchs perverted privatization, we overlooked it. When Russian elections were rigged or corrupted, we excused this as long as we liked the outcome. And when Russia destroyed Chechnya, we ignored it.

We told ourselves Russia would behave better if we used flattery, so we invited it into the G-7. We abandoned our concerns about allowing Europe to rely on Russian energy. And when Vladimir Putin, a man raised in the KGB, rose to power, we decided we could work with him.

The invasion of the nation of Georgia in 2008 produced a momentary chill — but it was followed by the Obama reset. Only since the election of 2016 — when Russia became a partisan issue — have Russia skeptics gained the upper hand over the appeasers.

And then there are the poster children for misplaced hopes, the Palestinians. There is no more reliable cliché in American foreign policy than the belief that the key to peace in the Middle East is to settle the dispute between the Israelis and the Palestinians.

This simply isn’t true. The roots of the strife in the Middle East rest in the dictatorial Arab and Iranian regimes as a whole, not the West Bank. But that hasn’t stopped a generation of U.S. presidents from accepting the cliché. From Clinton through Obama, and now to Jared Kushner, U.S. administrations have indulged in the heroic myopia of obsessing about the Palestinians.

We have other long-held, bipartisan, misplaced beliefs — like the idea that trading with China would transform it politically, or the fantasy that the European Union believes in democracy and will someday develop an effective military force. The question is why we believe so much that isn’t so.

The answer says something about us that isn’t entirely bad. All of our illusions reflect our deep-seated hope that the world wants to be prosperous and peaceful. Unfortunately, they also reflect our tendency to believe that deep-rooted problems can be fixed by doing things we like to do: spending money, doing business and cutting deals.

There is such a thing as the national interest, one that ought to be beyond party politics. But we’d be better off if we had less consensus about topics ranging from North Korea to the European Union, because often the consensus we have is wrong.

Ted R. Bromund is a senior research fellow in The Heritage Foundation’s Thatcher Center for Freedom.