Actual collusion involving the President would be hard to find. It is entirely possible that Mr. Trump lied about some of the meetings, or his knowledge of them (he lies about many things), and such lies could be impeachable offences. But impeachment is a political process; it would require a majority of the Republican-dominated House of Representatives to believe that trying Mr. Trump would improve re-election prospects in their districts, and then for two-thirds of Senators to believe that convicting him would please their own constituents. Mr. Trump remains popular among Republican voters.

Masha Gessen, the veteran Russian journalist who was forced to flee to the United States because of Mr. Putin’s persecution, has dismissed the possibility of any collusion being found as “vanishingly small” – and as a distraction from the real Putin-Trump problem. “Russia has served as a crutch for the American imagination,” she writes – Americans believe that when the conspiracy is exposed, “our national nightmare will be over.”

But it won’t. The larger Trump problem involves not control and manipulation, but influence and support. We should fear him not because of secret plots, but because he admires and imitates Mr. Putin’s ideas and strategies – right out in the open.