At the start of the weekend, President Trump was buoyant, exulting that Robert Mueller’s latest round of indictments had not shown any evidence that the Trump campaign colluded with Russia. (Never mind that the troll-farm attacks are just one of several spheres Mueller is investigating, and that far more evidence to suggest collusion has turned up in others.)

But by the mid-weekend, the president’s mood had soured, as it became clear to him that the prevailed narrative from the indictment was the “incontrovertible” proof—to use National-Security Adviser H.R. McMaster’s word—of Russian interference in the 2016 election. Nothing sets Trump off quite as consistently as any suggestion of anything that might undermine the legitimacy of his victory.

As I wrote on Sunday, this defensiveness usually backfires. By refusing to even acknowledge the Russian interference, Trump only calls attention to himself, and makes his reaction seem suspect. The president is making another point here, though, too: What about Obama?