Since the start of the Trump-Russia collusion fantasy, we’ve seen a pattern: On the eve of any report or fact that might undermine that narrative, the forces behind the FBI investigation leak a “bombshell” claim designed to further justify their actions. Bear this in mind when reading the new desperate—and highly irresponsible—reports about that supposed “high-value” Russian spy.

First CNN, and now a volley of outlets, are claiming that the U.S. government in 2017 was forced to pull out—or “exfiltrate”—a supremely covert Russian...