Even without the widening scandal over election interference, President Trump would have had a hard time managing America’s relations with Russia, which are as tense as at any time since the end of the Cold War.

The complex differences between the two countries will not be easily resolved. Moreover, President Vladimir Putin has shown a ruthless commitment to self-preservation that relies heavily on returning Russia to a mythical place of power and glory, not in helping the West build a more stable world.

Mr. Trump is making sound policy making even harder, though, with his admiration of Mr. Putin and his willingness to surrender the country’s international leadership, which was on display during the Group of 20 meeting in Germany. Mr. Trump is noticeably more comfortable with Mr. Putin than he is with most of America’s democratic allies, despite Mr. Putin’s record of crushing domestic opponents, invading Ukraine and bombing civilians in Syria.

There is nothing wrong with Mr. Trump’s ambition to improve relations with Moscow, given Russia’s importance as a nuclear weapons superpower with a United Nations Security Council veto. But that does not mean it is wise to underestimate, as Mr. Trump seems to do, the threat posed by Mr. Putin’s efforts to weaken NATO and the trans-Atlantic alliance, subvert democratic procedures and institutions in Europe and America, wage cyberwarfare, destabilize Ukraine and secure influence in Syria. Some Trump administration officials recognize those hazards; Mr. Trump does not.

One example is the mixed signals he is sending about maintaining sanctions on Russia. On Air Force One to Paris on Wednesday, he told reporters, “I would not and have never even thought about taking them off.”

Yet in the next breath, he confirmed that he discussed the issue briefly with Mr. Putin and left open the door to easing sanctions as part of a deal over Ukraine or Syria. Secretary of State Rex Tillerson sent a stronger message in Kiev last week when he assured Ukraine’s leader that sanctions won’t be lifted until Russia restores Ukraine’s “territorial integrity.” The problem: Mr. Trump has overruled Mr. Tillerson before.

Last month, concerned about Mr. Trump’s possible capitulation, the Senate approved, 98 to 2, legislation that would impose tough new sanctions on Russia for meddling in the 2016 election and allow Congress to block the president from lifting any sanctions in the future, including those relating to Ukraine. The bill has been stymied by partisan wrangling in the House, and the White House has tried to weaken it. Ordinarily, a president should have flexibility to lift or tighten sanctions, but Mr. Trump’s intentions are so suspect that this bill has become a necessity.

With Russia’s oil-dependent economy in trouble, Mr. Putin wants all sanctions lifted now. His aides are also pressing Washington to return two diplomatic compounds in Maryland and New York that were seized as part of the Obama administration’s response to the election meddling and were reportedly used for spying. But there is no reason to entertain these requests until Mr. Putin has pledged not to interfere in future American elections.

Mr. Trump also seemed far too solicitous in agreeing with Mr. Putin to create a joint working group on cybersecurity, an offer Mr. Trump withdrew after an avalanche of bipartisan criticism.

The bottom line is that Mr. Trump’s obsequiousness has yielded few results. Russia is still occupying Crimea, which it annexed in 2014, and is intensifying the war in the east against Ukrainian government forces, despite promising in the 2015 Minsk agreement to halt the fighting. Nor has Mr. Trump persuaded Mr. Putin to increase economic pressure on North Korea, whose nuclear program is now dominating the administration’s foreign policy; to stop the dangerous face-offs with American warplanes over the Baltic Sea; or to come back into compliance with the Intermediate-Range Nuclear Forces agreement of 1987 by withdrawing the deployment of a banned missile.

There are some hopeful signs, including a limited cease-fire in southwestern Syria. And the administration appointed a well-regarded former American ambassador to NATO, Kurt Volker, who is known for tough views on Russia, as special envoy to work with Russia on Ukraine. But on a wide range of issues, Mr. Putin seems unwilling to cooperate, and Mr. Trump doesn’t much seem to care.