The biggest story of the Senate Judiciary Committee hearing scheduled for Wednesday might be about the people who aren't there.

The chairman, Sen. Charles Grassley, R-Iowa, and ranking member, Sen. Dianne Feinstein, D-Calif., wanted Donald Trump Jr., the president's oldest son, and Paul Manafort, the president's onetime campaign chairman, to appear and testify — either voluntarily or involuntarily, if necessary, under subpoena.

Those witnesses said they agreed — but they arranged with the committee to do so in private as opposed to under the TV lights.

So did a third player in the Russia imbroglio who so far hasn't had anything like the public profiles of the other characters: Glenn Simpson, the founder of the political research shop Fusion GPS, which originated the infamous, unverified dossier of allegations against Trump that exploded onto the scene ahead of his inauguration earlier this year.

Simpson also cut a deal with Chairman Grassley in which he'll speak with committee members or staffers privately in the way Trump's son-in-law, Jared Kushner, did this week with the Senate and House Intelligence Committees.

So if you subtract the president's son, former campaign boss and a leading antagonist from a hearing about the sprawling Russia melodrama, what's left? Fewer political fireworks, in all likelihood, but a session that may still shed some light on some of the most shadowy practices in the capital: the advocacy of foreign governments.

Grassley's hearing is expected to revert to something like the one he originally convened and scheduled for last week: an inquiry into the little-known and — critics say — little-enforced Foreign Agents Registration Act.

Sovereign nations lobby Congress, conduct public affairs campaigns and do many of the same types of influence work in Washington as big American companies or unions or other interests. But the people foreign governments employ to do that work have a special set of rules they're supposed to follow.

The complaint by Grassley — and one made for years by watchdogs and would-be reformers — is that those rules aren't treated seriously. In fact, the original notice for the hearing included sarcasm parenthesis: "Oversight of the Justice Department's (Non) Enforcement of the Foreign Agents Registration Act: Lessons from the Obama Administration and Current Compliance Practices."

The witnesses are three officials from the Justice Department and the FBI, including one — Assistant FBI Director Bill Priestap, who has already appeared in at least one hearing in the Russia imbroglio.

He warned the Senate Intelligence Committee in June that Russia "absolutely" would continue with "influence operations" in the U.S. and the West focused on elections and other targets, like the ones Moscow launched in the 2016 election.

The others witnesses include the head of the Justice Department's National Security Division, Adam Hickey, and its inspector general, Michael Horowitz.

Also scheduled to appear is financier Bill Browder, who is expected to shed more light on the practices of Russia's government and its ties to one particular person in the story.

Browder once employed a Russian auditor, Sergey Magnitsky, who documented abuses by powerful Russians of its laws and tax code. Magnitsky was jailed over his disclosures and died in custody, prompting sanctions by Congress imposed under an eponymous Magnitsky Act.

That bill outraged Russian President Vladimir Putin, who retaliated by prohibiting American couples from adopting Russian children, and has worked ever since to shape his own narrative about Magnitsky and try to convince Congress to repeal the Magnitsky Act.

That has been the focus of two of the Russian advocates who took part in the Trump Tower meeting in June 2016: attorney Natalia Veselnitskaya and lobbyist Rinat Akhmetshin. It was Browder who was among the first to identify Akhmetshin publicly, having followed his work closely, and Browder's testimony on Wednesday could shed new light about what he knows about Russia's advocacy inside the United States and specifically how Veselnitskaya and Akhmetshin fit in.

Browder appeared Tuesday on WAMU's show 1A.

On Wednesday, Grassley wants to make the point that all these operators are buzzing around inside the United States and doing their work on behalf of their foreign masters — but Congress and ordinary Americans only know about it some of the time. He complained to then-Acting Deputy Attorney General Dana Boente about it all earlier this year.

"This is exactly the type of activity Congress intended to reach with FARA," Grassley wrote. "When properly enforced, FARA provides important transparency. However, in this case, because none of the parties involved in the anti-Magnitsky lobbying had properly registered under FARA, these suspicious connections were not appropriately documented and brought to public light."

Copyright 2021 NPR. To see more, visit https://www.npr.org.