It’s not just The Donald. Since World War II the Kremlin generally has seen most Republican presidents more benignly than their Democratic counterparts. Russian leaders generally believe Republicans are less wedded to unfriendly ideologies, such as human rights, and are more pragmatic. And when a Republican cuts a deal, they believe, it is more likely to stick. Republicans come across as honest adversaries who understand the language of power.

The Kremlin has disdained—and under-estimated to its later regret—two Democrats it saw as weak: John Kennedy and Jimmy Carter. At a premature 1961 Vienna summit Nikita Khrushchev went hard at Kennedy, who later confessed, “He beat the hell out of me.” The next year an overconfident Khrushchev attempted secretly to install nuclear missiles in Cuba, but made an embarrassing retreat after Kennedy imposed a naval quarantine of the island.

In 1979 the USSR invaded Afghanistan, but did not count on Carter’s response. He organized a multi-nation boycott of the 1980 summer Olympics in Moscow, and imposed an embargo on sales of U.S. grain needed to boost Soviet meat production. Carter also led a robust NATO counter to a missile build-up aimed at Europe and Japan.

The Kremlin has distrusted Democratic crusaders. In 1945 Harry Truman intoned, “we have to get tough with the Russians…teach them how to behave.” He sent aid to Greece and Turkey to counter communist guerrillas, mounted an airlift to halt a Soviet blockade of West Berlin, and led creation of the NATO military alliance. Weeks after assuming office in 1977 Carter wrote dissident Andrey Sakharov and voiced support for human rights, so angering the Kremlin that it rebuffed Carter’s proposal for nuclear arms cuts.

Although Moscow was angered by early anti-Soviet rhetoric from two Republicans, Dwight Eisenhower and Ronald Reagan, it came to appreciate their pragmatism. The Soviets respected Eisenhower as a World War II comrade-in-arms. Despite his campaigning in 1952 against “Korea, communism and corruption,” Ike worked out a Korean War armistice, slashed defense spending, and responded with restraint to the 1956 Soviet invasion of Hungary. Yet peaceful coexistence did not stop Khrushchev from humiliating Eisenhower in 1960 after he lied about a U-2 spy plane shot down over the USSR.

Reagan also began with tough rhetoric. Only days after his 1981 inauguration he said the Soviets “reserve unto themselves the right to commit any crime, to lie, to cheat.” The Kremlin was grateful that he quickly ended the grain embargo, but alarmed when he banned exports to the USSR of high-end energy technology, built up U.S. strategic nuclear forces, and called for futuristic missile defenses.

Soviet leaders took Reagan’s rhetoric seriously, opened archives later showed. Realizing that the USSR could not keep up, Mikhail Gorbachev began reforms after he came to power in 1985. He and Reagan negotiated a historic relaxation of tensions, including a first-ever treaty to ban a whole class of intermediate-range nuclear forces.

Gorbachev regarded George H. W. Bush as an even closer partner. Bush eased pressure as Gorbachev allowed the Berlin Wall to fall in 1989, withdrew Soviet forces from Eastern Europe, and acceded to the reunification of Germany. Despite rising ethnic nationalist pressures, Bush for awhile backed Gorbachev’s efforts to hold the USSR together. Although at first wary of Boris Yeltsin, Bush and the elected Russian President jointly declared an end to the Cold War and agreed to cut sharply the sides’ strategic nuclear forces.

Bill Clinton may have been the Kremlin’s favorite Democrat. He backed Yeltsin’s bold but erratic reforms. Clinton muted criticism of Yeltsin’s controversial shelling of a renegade parliament and of his launch of a calamitous war against Chechnya. Yeltsin returned the favor by not objecting strongly when NATO took in several former Warsaw Pact countries.

George W. Bush may have been the Kremlin’s least favorite Republican. After the September 11, 2001, terrorist attacks, Putin was the first foreign leader to call and offer help. Relations soured after the 2003 U.S. invasion of Iraq, popular uprisings in Georgia and Ukraine that Putin blamed on America, the 2008 Russian invasion of Georgia, and the 2008-09 financial crisis in Russia.

Relations with Barack Obama began well, but he soon became another disliked Democrat. Under an early effort to “reset” relations, the two sides agreed on logistics support via Russia for NATO forces in Afghanistan and on an accord that further cut strategic nuclear forces. Obama turned more critical in 2013, after Edward Snowden leaked thousands of classified documents to the press and the Russian Duma unanimously passed a bill that criminalized organizing for LGBT equality.  After the seizure of Crimea and armed intervention in eastern Ukraine in 2014, the West imposed unprecedented sanctions.

Kremlin advisor Sergey Markov recently claimed that it would be unusual for Russian officials to publicly take sides in a U.S. election. “Prudence usually overrides preference… endorsing a losing candidate can bring eight years of bad luck.”

Nevertheless, the Kremlin may see Donald Trump as in a category by himself. His views on NATO and Ukraine seem close to Russia’s own. Trump has said of Putin that he was honored to be “complimented by a man so highly respected.” At the Republican convention in Cleveland, Trump lieutenants gutted a platform call for lethal defensive military aid to Ukraine.

“Because Trump is anti-establishment,” Markov said, “he more carefully listens to the so-called ‘silent majority’ of the American nation, who do not want a conflict with Russia.” A majority of Russians would like a Trump win, according to a recent poll by the British research firm YouGov.

The Kremlin dislikes Hillary Clinton. After a stolen parliamentary election in 2011 that led to large public protests, Putin blamed then-Secretary of State Clinton for sending a “signal” to “some actors” in Russia. In the past she has been tougher on the Kremlin’s human rights violations than even President Obama.

While the Kremlin relishes boosting Trump to cause chaos and rattle the Clinton campaign, however, they may be doing so now because they have calculated that Trump’s chances of winning are in fact low.  Despite all the surface gloss from Trump about “deals” and his sweet words about Crimea belonging to Russia, they likely realize that a Trump presidency would be the farthest thing from “Republican” in the traditional sense.  Clinton would be far more of a “Republican” than Obama.  She would be distasteful, but at least be predictable.

For a quarter-century U.S. policy toward Russia has been largely bipartisan, in contrast to Cold War-era Washington infighting. Despite sharp differences between Clinton and Trump, enduring interests and influences may favor continued consensus. But Trump has upended so many assumptions about U.S. politics that one cannot expect it to remain if he wins.