Former Trump lawyer and fixer Michael Cohen is scheduled to appear before three congressional committees this week before he heads to jail to serve a sentence for tax evasion and lying to Congress. On Tuesday, Cohen will testify before the Senate Intelligence Committee. On Wednesday, he will go before the House Oversight Committee. And on Thursday, he will testify before the House Intelligence Committee.

It would be a great service if the Cohen appearances helped increase the store of public information on the Trump-Russia furor. But even though Cohen is a key figure in the matter — his name is mentioned 24 times in the so-called Trump dossier — the hearings appear designed to prevent the public from learning anything new about the Russia matter.

First, two of the three hearings will be held in secret; both the Senate and House Intelligence committees plan to question Cohen behind closed doors. Those are the hearings that will delve into Russia. The hearing that is public, before House Oversight, is specifically structured not to touch on the Russia matter.

There is good reason for all the questioning to be public. Cohen is not a government official and has no classified information to share. His 24 mentions in the dossier have been publicly available for two years. His conviction on lying to Congress — specifically, his falsehood about the timing of Trump Tower Moscow discussions — is also public. His own case is over and done with, and he will soon be behind bars.

Furthermore, Cohen has already answered questions from the House Intelligence Committee, and all members, Democrat and Republican, voted to make those answers public. "There's no reason to prevent him from testifying publicly since he previously spoke to us in an unclassified setting, and the Democrats supported our motion in the last Congress to publish our interview transcripts," said Intelligence Committee ranking Republican Rep. Devin Nunes, a former chairman of the committee. (The Cohen transcript has still not been publicly released; GOP lawmakers say the intelligence community is dragging its feet on a routine pre-release review.)

Some might argue that with the investigation of Trump-Russia special counsel Robert Mueller not yet closed — although there are reports that is coming soon — Cohen should not speak publicly about an ongoing investigation. But the fact is, on Feb. 6, Intelligence Committee Chairman Rep. Adam Schiff announced a new Russia investigation that will, if carried through, recover much of the same ground as Mueller. That means what Cohen has to say about the Russia affair is now the subject of an ongoing House investigation — the Schiff investigation — and the House owes it to the public to conduct the probe in public.

Instead, Schiff will keep Cohen's answers under wraps.

Over at the Oversight Committee, the one that will be open, Chairman Rep. Elijah Cummings has ruled the hearing will not be about Russia. "The scope of the Oversight Committee's open public hearing will not include questions relating to the Intelligence Committee's investigation of efforts by Russia and other foreign entities to influence the U.S. political process during and since the 2016 U.S. election," Cummings wrote on Feb. 20. Also off the table, Cummings said, is "the counterintelligence threat arising from any links or coordination between U.S. persons and the Russian government, including any financial or other compromise or leverage foreign actors may possess over Donald Trump, his family, his business interests, or his associates."

That's pretty much the whole Russia story, and it won't be told in Cummings' hearing room. "The Cohen hearings are designed to keep the Russia collusion narrative alive by keeping key witness testimony hidden," Oversight Committee Republican Rep. Mark Meadows told me in a text exchange.

What will the public Cohen hearings be about? After consulting with the Justice Department and with Schiff, Cummings released a list of topics that might be damaging or embarrassing to the president but would reveal little or nothing about the allegation that the Trump campaign and Russia conspired to fix the 2016 election. Among the approved topics: the Stormy Daniels payments; Trump's compliance with campaign finance laws; Trump's compliance with tax laws; Trump's "business practices"; the Trump International Hotel in Washington; the "accuracy of the president's public statements"; potential fraud by the Trump Foundation, and more.

Of course, Cummings is the chairman of the committee, and he can pick any topic he likes. And Congress can investigate the president's business dealings as much as it chooses. But the combination of Cummings' anything-but-Russia topic list and Schiff's secrecy means that the public's only chance to hear from Cohen will not touch the topic that has dominated the Trump presidency and American politics for more than two years.

The only people who might throw a wrench in the works are Oversight Committee Republicans. They are free to ignore Cummings' directive and ask Russia-related questions. Cohen has long denied key dossier allegations, but what can he add today? What about the infamous Trump Tower meeting? The Trump Tower Moscow matter? Any other Russia issues?

"We're going to ask whatever we want to ask," said one committee Republican late Monday.

Cohen might not answer the questions, and the chairman might take Cohen's side, but Republicans can at the least remind viewers that the Democrats who run the House, after talking Russia nonstop for two years, now don't want to talk publicly about the subject, even with a star witness sitting in front of them.