If you believe in diplomacy as a means to solve, or at least mitigate problems, it generally means welcoming even eyes-wide-open diplomacy conducted with adversaries.

So it is perfectly natural for the President of the United States to meet with the President of Russia, even one as troublesome and cynical as Vladimir Putin. Presidents from Eisenhower to George H.W. Bush met with Soviet leaders throughout the Cold War.

But what is not natural at all is the degree to which both sides seem to want to use such a summit to serve Russian interests.

Administration spokespeople, in discussing President Donald Trump’s upcoming meeting with President Putin in Helsinki, have offered scant indication of what Trump wants to achieve from this summit, what interests of the United States he seeks to advance. He wants a "good relationship" with Putin, we are told.

Meanwhile, it is perfectly clear what interests of Russia Putin aims to advance.

First, he wants to ease pressure and sanctions on Russia imposed in response to its aggression against Ukraine.

And sure enough, at the G-7 summit in Canada last month, Trump advocated including Russia in the gathering, and went so far as to justify Russia’s illegal annexation of the Crimean peninsula - because there are many Russian speakers there. In recent days, he has refused to rule out U.S. recognition of Russia’s land grab.

Second, Putin seeks to weaken the Western alliance and take steps toward breaking up a united Europe, both of which he perceives as a threat and challenge to Russia. These are longstanding Russian goals.

As if on cue, as Trump prepares to attend the NATO summit ahead of his meeting with Putin, he lobs nearly daily verbal assaults at the United States’ closest allies.

He has downplayed NATO’s value and even floated the outlandish notion that the United States should withdraw from the alliance. Moreover, after cheering on Brexit he has encouraged other nations to leave the European Union, reversing decades of American strategy to support a united Europe as a source of stability on the continent. To top it off, he launched a needless trade war, imposing tariffs against our European and Canadian trading partners.

Open gallery view President Donald Trump meets with French President Emmanuel Macron during the G-7 summit, Friday, June 8, 2018, in Charlevoix, Canada Credit: Evan Vucci/AP

Third, Putin hopes the world will forget, or overlook, that Russia interfered in the U.S. elections in 2016.

Trump’s response? He testifies on Twitter that "Russia continues to say they had nothing to do with Meddling in our Election!" He seems to believe Putin’s claims more than the unanimous conclusions of America’s intelligence agencies. And his administration is doing next to nothing to prevent more Russian intervention in the 2018 elections.

Finally, Putin wants the world to accept that the genocidal Assad regime has returned to stability and is restoring its rule over the vast majority of Syrian territory.

And Trump has made clear, despite the objections of his advisers, that he wants U.S. forces to leave Syria, the sooner the better. Already, the United States has sent messages to the moderate opposition groups in southern Syria that they should no longer count on American assistance, and that they resist Assad’s forces at their own risk. Predictably, Russian airstrikes are wiping them out.

But wait. Maybe here, at least, we can detect a U.S. interest, and even an Israeli one, that could be served by this summit.

Open gallery view Iran's army chief of staff Maj. Gen. Mohammad Bagheri, left, with senior officers from the Iranian military as they visit a front line in the northern province of Aleppo, Syria. Oct. 20, 2017 Credit: /AP

There are suggestions that Russia can be convinced to push Iran out of Syria, or at least substantially limit its military presence. If that were to take place, it could dramatically reduce the risk posed to Israel from Iranian missiles, drones, and Shia militia based in Syria.

Such an arrangement could be accompanied by Russian guarantees of Israeli freedom of action against Iranian, or other, threats in Syria, provided no Russian troops are harmed and the Assad regime is not put at risk.

For three years, thanks to Prime Minister Netanyahu’s skillful diplomacy with Putin and the IDF’s precise operations, Israel has, with U.S. support under both Obama and Trump, successfully targeted Iranian weapons and forces in Syria - while avoiding Russian blowback that could constrain Israel’s ability to strike.

If he secures such understandings, Trump would be able to explain his decision to accommodate Russia in Europe and withdraw U.S. troops from Syria as a win: he ends a U.S. military engagement in the Middle East and Iran’s regional ambitions are rolled back, protecting Israel from a clear and present danger.

It sounds too good to be true. It is.

Open gallery view Russian President Vladimir Putin, Serbian President Aleksandar Vucic, and Israeli Prime Minister Benjamin Netanyahu, after the WWII Victory Parade in Moscow, Russia. May 9, 2018 Credit: Alexei Druzhinin/AP

Two problems: First, the cost. Such a deal, even if it held, would come at unimaginable harm to U.S. interests in Europe. More than one senior Israeli official has suggested to me that the United States should, in effect, "trade Ukraine for Syria": look the other way at Russia’s takeover of portions of Ukraine as the price for Russia expelling Iran from Syria. I can understand why Israelis, focused on regional dynamics and the threats they face, would embrace such a calculus.

But I cannot imagine any U.S. strategist willingly giving Russia a free hand in Eastern and Central Europe, even for the noble cause of constraining Iran. Unless that "strategist" seeks to dismantle the Western alliance. It won’t stop with Ukraine. Without the alliance that has anchored European security for 70 years, dark days could lie ahead for the Baltic states and others Putin seeks to dominate. Even Israelis should have pause if the price of removing Iran from Syria is the dismantlement of NATO.

Second, the reliability. The "deal" imagined here leaves Russia as the sole actor determining what is allowed to take place in Syria. If it serves Putin’s interests for now to constrain Iran, he will do so. And if he recalculates his interests - if he sees he could gain further regional advantage by being more permissive to Iranian ambitions - nothing would stop him. Israel will still be able to act in its own self-defense.

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But the strategic gains of an Iranian rollback are dependent on a single factor: Putin’s word. Who wants to base any strategy on putting trust in that?

Securing Russia’s commitment to expel Iran from Syria is a worthy goal. Sacrificing decades-old U.S. interests is not the way to get it.

Israelis focused on the Iranian threat can be forgiven for placing hope in the path Trump is beating to Helsinki. But the course he is on will produce only one winner: Russia.

And Netanyahu, an admirer of Churchill, would be wise to remember his words: "An appeaser is one who feeds a crocodile, hoping it will eat him last."

Daniel B. Shapiro is Distinguished Visiting Fellow at the Institute for National Security Studies in Tel Aviv. He served as U.S. Ambassador to Israel, and Senior Director for the Middle East and North Africa, in the Obama Administration. Twitter: @DanielBShapiro