Russian efforts to influence the U.S. political system have fascinated the American media for much of the past year—but not this week. A sudden and likely temporary loss of appetite to explore collusion theories seems to have developed early on Tuesday.

That’s around the time that The Hill began breaking a series of stories on Russia’s efforts to influence Obama Administration policy and advance the interests of the Russian nuclear industry. Expect the condition to persist until the next leak from special counsel Robert Mueller’s...