House Intelligence Committee Chairman Devin Nunes (R-Calif.) speaks with reporters outside the West Wing of the White House in Washington on March 22. (Jabin Botsford/The Washington Post)

ANYONE PAYING attention to the mushrooming investigations into Russian meddling in the 2016 U.S. election campaign and President Trump’s possible ties to Moscow will have noticed that this is not a simple story. At issue are complex questions of espionage, counterintelligence, unlawfulness, secrecy, sovereignty and coverup. It will be hard enough for the ongoing probes by the FBI, Congress and special counsel Robert S. Mueller III to sort out the mess and come up with the truth and reach credible conclusions.

That is why the latest maneuverings of House Intelligence Committee Chairman Devin Nunes (R-Calif.) are disturbing. Mr. Nunes, it should be recalled, announced in April that he would step aside from the panel’s investigation into the Russia affair. He recused himself after odd feints that appeared to be nothing more than an effort, in conjunction with the White House, to confuse the probe by highlighting Trump’s dubious claim that he was wiretapped by the outgoing administration. Now it appears Mr. Nunes isn’t quite stepping away, and that is reason for new concern.

In the latest twist, Mr. Nunes was reported on Wednesday to have issued a series of committee subpoenas to the CIA, FBI and National Security Agency for information on “unmasking.” U.S. intelligence rules provide procedures for when intercepts of foreign nationals pick up the names of American citizens; they can be unmasked only if the procedures are followed. The claim Mr. Trump and others have made is that the Obama administration improperly unmasked names of Trump associates in intercepts recorded during the election and transition.

The Nunes action seems unnecessary; if anything improper was done, the committee is capable of checking into it. This is not a separate matter from the Russia story, and Mr. Nunes’s recusal means he should keep his hands off it. Suspiciously, right after Mr. Nunes issued the subpoenas, Mr. Trump tweeted, “The big story is the ‘unmasking and surveillance’ of people that took place during the Obama Administration.”

No, it is not. The “big story” is whether Russia brazenly attempted to tilt the U.S. election by damaging Hillary Clinton through a cyberattack and other means, thereby helping Mr. Trump to victory, and whether members of the Trump campaign colluded in that effort. It’s about Mr. Trump’s ill-explained and gratuitous attempts during the transition and since to do the bidding of Russian President Vladimir Putin, including trying to unwind the sanctions against Russia imposed by President Barack Obama after the election meddling was discovered.

The “big story” is why Mr. Trump has frantically attempted to shut down the Russia investigations, including through the firing of FBI Director James B. Comey. It’s about getting an answer, once and for all, about Mr. Trump’s finances and any undisclosed links with Russia. The unmasking that’s important is the truth behind all this. Now it is in the hands of the investigators, and they must be left to do their work properly and without interference by Mr. Trump — or Mr. Nunes.