The devil lies in the definition. Bill Clinton “never had sex with that woman”, and got away with it. Jeff Sessions never had “communication” with a Russian ambassador, Sergei Kysliak. But it depends what you mean by sex, and what you mean by communication.

Whether or not Sessions, now “America’s top cop”, as attorney-general, lied to his colleagues or whether, like treason, lying is a matter of dates, should not matter – or not much. What matters is what on earth was going on between Donald Trump and the Russians before Trump became president. Sure as anything, something was.

Russia is supposed to be America’s greatest enemy. Trillions of dollars still go into confronting the Kremlin. Russia has long been the dominant declared “threat” to America, Europe, disarmament and peace on Earth. It is aggressive and undemocratic. Every American sinew for half a century has been directed at curbing, punishing, impoverishing and humiliating Russia and its leaders (now Vladimir Putin).

Suddenly, along comes an American president, indeed a rightwing one, who seems to be thick as thieves with Russia. He declares he likes Putin and wants to get on with him. He is Trump’s kind of guy. So Trump’s election team, somewhat recklessly, put out early feelers.

Those of us who have felt the American – and British – approach to Russia since 1990 has been provocative, ham-fisted and counterproductive might cheer at all this. Barack Obama too wanted to “reset relations” with Russia, and failed. Might Trump succeed?

So why has Trump’s “opening to the east” seemed so underhand, so enveloped in mendacity and denial? Why not come clean and declare a massive and constructive change of policy? Let’s try to get inside Putin’s insecurities, notably in relation to his neighbours. He could just say: let’s stop fatuous sanctions, which help no one and hurt many, and establish red lines round areas of aggression and areas of agreement and cooperation; let’s use soft as well as hard diplomacy.

The answer may be that Trump is plain naive and lacking in executive competence. His accident-prone appointees seem not up to their jobs. Rumours abound that Trump has had some link to Putin’s sinister finances. Anyway, if he really intends a seismic shift in western policy towards Russia, the more we know about the backstory the better. Congress has set up a hue and cry, and tends to do these things thoroughly. Trump would be well advised to come totally clean.

But let’s not lose sight of the wood for the trees. Given all the world’s instabilities, a rapprochement between America and Russia is a truly worthwhile objective. Its capacity to relieve tension, release resources, combat poverty and save lives is colossal. A few lies and stumbles along the way would be a price worth paying.