The Wall Street Journal | Walter Russell Mead: Rarely has an American president been as isolated on foreign policy as President Trump is today. The Senate voted 97-2 to support the North Atlantic Treaty Organization last week, even as Mr. Trump belittled NATO and its principal members. Meanwhile, both the Justice Department and the director of national intelligence are sounding the alarm about the Russian leader Mr. Trump appears to be trying to recruit as an American ally. The president’s policy of reconciliation with Russia at the expense of NATO has even less support in Washington than President Obama’s policy of breaking with Middle East allies to attempt a reconciliation with Iran.

Among the president’s remarkable assumptions about Vladimir Putin’s Russia: that it can be induced to cooperate with the U.S. on a wide range of security issues, including Syria and Iran; and that it can replace Germany as America’s principal Eurasian partner—or, if not, the U.S. can use the threat of a Russian alliance to extract better terms from Germany and the European Union. The president is confident that he possesses the bargaining ability and diplomatic talent to manage the complex negotiations involved.

Why does Mr. Trump seem so determined to defy his advisers and play a Russia card that costs him dearly in Washington and nourishes the suspicions of the investigators probing his Russia connections? His fiercest critics are sure they know the answer: Vladimir Putin has “compromised” the president, leaving him no choice but to appease the Russian dictator.

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