If there is an obstruction of justice case to be made against the president in the Trump-Russia affair, James Comey is in the middle of it. President Trump's decision to fire the FBI director is often cited as Exhibit A for obstruction, and the foundation for that case is a set of seven memos Comey wrote describing conversations he had with the president between Jan. 6 and April 11, 2017.

The memos are critically important. Portions of them have been leaked to the press, given to a Comey friend, discussed in congressional testimony, and read by a few Capitol Hill lawmakers and staff. Sometimes it seems the only people who have never had a chance to see the Comey memos are the millions of Americans who are trying to make sense of the daily firehose of Trump-Russia news.

They're not likely to see the memos anytime soon. The FBI and the office of Trump-Russia special counsel Robert Mueller have imposed tight restrictions on access to the memos, holding them even more closely than some documents that are classified at a far higher level. Now, with speculation about obstruction ever present in the media, some lawmakers are calling for the memos to be released. It's time for Americans to know what's going on, they say.

The public part of the memo story began on May 16, 2017, when the New York Times published a story headlined, "Comey Memo Says Trump Asked Him to End Flynn Investigation." The paper reported that a Comey-penned memo detailing a Trump-Comey conversation the day after the firing of national security adviser Michael Flynn was "part of a paper trail Mr. Comey created documenting what he perceived as the president's improper efforts to influence a continuing investigation."

"An FBI agent's contemporaneous notes are widely held up in court as credible evidence of conversations," the Times added.

Members of Congress investigating the Trump-Russia affair, both House and Senate, Democrat and Republican, clamored to see the Comey memos. In a letter dated May 17, 2017 — the day after the Times report — Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, and committee member Sen. Lindsey Graham, R-S.C., joined ranking Democrats Sens. Dianne Feinstein of California and Sheldon Whitehouse of Rhode Island to ask the FBI to "produce all such memos, if they exist."

Other committees made similar requests. As has been the case throughout the investigation, the FBI was not immediately forthcoming. When Comey made a hugely anticipated, post-firing appearance before the Senate Intelligence Committee on June 8, 2017, senators still had not seen the memos. They were forced to ask Comey questions not knowing what he had already written down.

Some lawmakers felt particularly aggrieved at the FBI's refusal to turn over the memos when they learned that Comey had given some of the documents to a friend, Columbia University law professor Daniel Richman, for the specific purpose of being leaked to the New York Times, with the ultimate hope that exposure would spur the appointment of a special prosecutor in the Trump-Russia case.

"I asked a friend of mine to share the content of the memo with a reporter," Comey told the Senate last June. "Didn't do it myself, for a variety of reasons. But I asked him to, because I thought that might prompt the appointment of a special counsel. And so I asked a close friend of mine to do it."

Within hours of Comey's testimony, the bipartisan group on the Senate Judiciary Committee fired off a letter to Richman asking for the memos Comey sent him. Richman said no. He wouldn't even say if he still had any of the memos. A few months later, the committee asked Richman to come in for an interview. He refused. Later, he claimed to be one of Comey's attorneys.

Finally, in July 2017, the FBI allowed lawmakers to see the memos. But the bureau made sure the information in the memo was severely restricted.

For the Senate Judiciary Committee, which directly oversees the FBI, the bureau allowed only two committee staffers to see the memos. They had to go to the FBI, and an FBI minder was in the room at all times. They were not allowed to make copies or take notes. The FBI later took the memos to the Senate to allow Grassley to read them. But the same rules applied: FBI minder, no copies, no notes.

The no-notes restriction was unusual, because committee staff had been allowed to take notes from the Trump-Russia Foreign Intelligence Surveillance Act, or FISA, applications, which were highly classified. Some of the Comey memos were not classified at all.

And, of course, both Republicans and Democrats on the Judiciary Committee had asked to be given the memos, not be given a chance to read them. That still hasn't happened. "The chairman and ranking member asked for copies of the memos," said a committee spokesperson Wednesday. "The FBI has yet to actually turn over those documents to the congressional committee tasked with overseeing the bureau and the Justice Department."

On the House side, Republican Rep. Trey Gowdy, R-S.C., among a few others, was allowed to read the memos under the same conditions: FBI minder, no copies, no notes.

What struck Gowdy was the general absence of classified information in the memos or any other reason they should remain secret. Out of a total of seven memos, the FBI had marked four as classified at the "secret" or "confidential" levels — not the highest level — but even with those memos, it appeared to Gowdy that they could be released publicly with only minimal blacking-out.

"What would need to be redacted would be incredibly small and really would not interfere with the substance of the memos," Gowdy told me in a phone conversation Wednesday. "I read them a long time ago, and I still don't know why they're not in the public domain. If they were really helpful for the Democrats, they would have been leaked a long time ago."

Rep. Devin Nunes, R-Calif., chairman of the House Intelligence Committee, has the same view. "Seeing as Comey already admitted leaking information from his memos to the press, I do think the memos should be released publicly," he said in a statement Wednesday.

So why the secrecy? Especially since the presence of what little classified material there is in the memos doesn't seem to present a problem.

A Justice Department spokesman did not answer an inquiry, but the FBI and Mueller have taken the position that secrecy is necessary because the Trump-Russia probe is an ongoing investigation. Mueller received support two weeks ago when a federal court in Washington denied a Freedom of Information Act request by news organizations to make the memos public. After repeated presentations from Mueller's office, Judge James Boasberg wrote, "the Court is now fully convinced that disclosure 'could reasonably be expected to interfere' with that ongoing investigation."

Boasberg wrote a detailed analysis of the legal arguments in the case. But with Capitol Hill involved, there is always a political side, too. And politically, there are at least five reasons why the memos should not remain secret. First is the public's right to know, which is strong in a matter of this importance. Second is the fact that there is not going to be an obstruction of justice trial for Trump; if there is any action against him, it will be the political process of impeachment, beginning in the House of Representatives, and the memos could play a key role. Third, Comey himself has already leaked portions of the memos. Fourth, Comey has already testified publicly about some of the same topics covered by the memos. And fifth, the FBI has already conceded the principle that Congress has a right to see the memos.

Mueller and the FBI remain unconvinced. That could be a matter of principle, or it could be that keeping the Comey memos secret protects Comey's — the star witness's — credibility. It's hard for anyone in public to test the memos', and Comey's, credibility while the documents remain hidden.

And then there is the public impression the memos might make. No one knows whether that would help or hurt Mueller's case. Comey told the Senate that he found some of Trump's statements "very disturbing" and "very concerning." But did he write in the memos that he felt pressured or pushed or that Trump was making an effort to obstruct the investigation? The answer is not clear. If there were an impeachment trial for Trump, it's uncertain whether the memos would prove more valuable to the prosecution or to the defense.

"I have read the memos," Gowdy said on Fox News "Special Report" Monday. "They would be defense Exhibit A in an obstruction of justice case — not prosecution exhibit, defense Exhibit A. If Comey felt obstructed, he did a masterful job of keeping it out of the memos."

Meanwhile, Congress is still trying to learn more about the documents. Last month, Grassley sent the Justice Department another letter trying to figure out who at the Justice Department had handled the memos. Judging by the committee's record, the chairman will keep at it until the public gets a chance to learn the whole story.