Congressional inquiries and special counsels can productively coexist, serving complementary purposes because of their reciprocal approaches, unless they’re unable to settle inevitable fights over the same documents and star witnesses.

That may be the best response to a question many on Capitol Hill started asking as soon as Robert S. Mueller III was appointed to run the government’s probe of Russian interference in last year’s election and whether Moscow collaborated with President Donald Trump’s campaign:

What’s left for lawmakers to do — indeed, what’s appropriate for them to do — now that the Justice Department has given the former FBI director broad latitude, independence of judgment and an open budget for getting to the bottom of Russia’s role?  

As Congress left town following the most tumultuous week of the nascent Trump administration, which turned four months old on Saturday, lawmakers were of two minds. Beyond their effusive bipartisan praise for Mueller and his above-reproach reputation, sentiment fell decidedly along party lines when talk turned to the special counsel’s impact on the Hill’s work.

Republicans heaved a collective sigh of relief, hoping a sustained and in-secret investigation lasting months would create a bad news blackout in which the Capitol’s attention could be refocused on conservative legislating. But, even if that doesn’t materialize, Mueller’s probe has given them ample justification for saying absolutely nothing more about the Russia-Trump imbroglio — not to reporters or their constituents and, in the view of many, not at Hill hearings that could complicate Mueller’s work.

“Congress has been pretty much sidelined, because we’re going to have to be very leery about steering into Mr. Mueller’s lane,” said GOP Sen. Lindsey Graham of South Carolina, who has been spearheading one of four congressional committee inquiries on Russia, after a closed-door briefing where Deputy Attorney General Rod Rosenstein detailed his reasoning for naming a special counsel.

Democrats declared that broad Senate and House inquiries into counterintelligence and other aspects of the Russia story should continue while Mueller pursued his more narrow assignment of searching for criminality.

“They are very different investigations,” Senate Minority Whip Richard J. Durbin said moments after Graham spoke. “We’ve still got a lot of work to do.”

Lessons from 44 Years of Special Investigations

Parallel paths

There does seem to be plenty Congress can tackle, through its own committees or by empaneling an independent commission, without getting in Mueller’s way.

This is because the two have fundamentally different roles to play, often divergent ways of going about their work, and ultimately, dissimilar objectives.

At the core, the House and Senate have oversight responsibilities to carry out as part of their constitutional brief, while Mueller has the exclusive responsibility of law enforcement.

The elected officials can draw a satisfied sense of accomplishment by focusing the nation’s attention on incidents and rhetoric that don’t pass the smell test — behavior by government actors that’s maladroit, ethically suspect, morally reprehensible, professionally bone-headed or palpably unpatriotic.

But the appointed counsel will get a “mission accomplished” badge only if he persuades a grand jury to return indictments alleging provable crimes, those charges produce guilty verdicts and those convictions are upheld on appeal.

The politicians, using the guaranteed publicity at their disposal, will be all about turning poor behavior into breaking news alerts and headlines — preferably in plenty of time for the next campaign.

The prosecutor, using the expectations of confidentiality at his disposal, will be all about turning bad behavior into violations of U.S. Code, Title 18 — whether that takes several months or several years.

The preferred venue for Congress to do its most consequential work is the court of public opinion. The only place where Mueller might win is the federal courthouse. Their job is fundamentally political, while his is entirely legal.

At a minimum, lawmakers can use investigations to inflict public embarrassment on foolish actors. At a maximum, they can persuade the electorate to get behind efforts to secure resignation of poorly behaved senior officials — or, in the most extreme case, to support their drive for impeachment. An impeachable offense, after all, is whatever a majority of the House and two-thirds of the Senate says it is.

In the end, special counsels have a binary choice. They can file criminal charges and lay out their case, or they can close up shop after offering their rationalization for why charges were not warranted. A criminal offense, after all, is whatever a dozen ordinary Americans are persuaded it is.

The job is to decide “whether government agents had engaged in bad acts, not whether they exercised bad judgment,” is how former GOP Sen. John Danforth of Missouri said it when his own assignment ended in 2003, without any criminal charges stemming from the fatal raid on the Branch Davidian sect compound in Waco, Texas.

Potential collisions

All that said, as Congress and Mueller maintain their interest in Russia, they will inevitably be hoping to make use of the same original source material — and that is where each has the potential to hobble if not ruin the work of the other.

For example, several Republican committee chairmen have already asked for the contemporaneous notes that James B. Comey kept of his encounters with Trump in the months before he was fired as FBI director — particularly the memo he reportedly wrote, after a February dinner in the White House, recounting the president’s request that he quash the investigation of Michael Flynn’s connections to Russia and other countries before his brief run as national security adviser.

But it’s unclear whether compliance with those congressional requests, even if they become subpoenas, would complicate the FBI’s efforts to help Mueller decide how to handle that same evidence.

The same will be the case when it comes to Comey’s own future appearances. He’s been asked by the GOP to appear before a handful of Hill panels, and his testimony could make for blockbuster political television.  

But accepting the invitation to illuminate the nation about his version of events could create legal or strategic problems down the line for Mueller. And since the two have been close colleagues in the ranks of premier federal prosecutors for two decades, it’s very likely Comey will put working with the special counsel behind closed doors ahead of sharing his own narrative on television.

Most important of all, though, will be whether Congress and Mueller can come to a shared agreement for handling witnesses more hostile than Comey — because they might be in career, if not criminal, jeopardy.   

The lawmakers, since they’ll be putting a premium on getting credit for explaining any malfeasance to the public, will be intent on getting the central players in the Russia probe to tell the whole truth on camera. But such appearances could prejudice juries or otherwise hobble a special counsel’s case later on.

And if Congress secures key witnesses with grants of immunity, promising that nothing they say on the Hill can be used against them in court, that would likely shield some of the worst actors from ever contemplating prison time.

That is the lasting consequence of the biggest power tussle ever between Congress and a special prosecutor.

Iran-contra independent counsel Lawrence Walsh could not prevent a special House-Senate investigative committee in 1987 from partly immunizing the testimony of John M. Poindexter, President Ronald Reagan’s national security adviser, or Oliver L. North, who, as a National Security Council staffer, helped coordinate arms sales to Iran and the diversion of some profits to the Nicaraguan rebels.

Walsh won their convictions after trials where what they said on the Hill was not repeated, but both saw their guilty verdicts thrown out by appeals courts that ruled other evidence had been tainted by testimony given under promise that it wouldn’t be used against them.