WASHINGTON — America has waited a year to hear what special counsel Robert Mueller concludes about the 2016 election, meddling by the Russians and — most of all — what Donald Trump did or didn’t do. But how much the nation will learn about Mueller’s findings is very much an open question.

Deputy Attorney General Rod Rosenstein may end up wrestling with a dilemma similar to the one that tripped up fired FBI director James Comey: how much to reveal about Trump’s actions absent an indictment against the president. Rosenstein, who lambasted Comey for disclosing derogatory information about Hillary Clinton despite not recommending her for prosecution, may himself have to balance the extraordinary public interest in the investigation against his admonition that investigators should not discuss allegations against people they don’t prosecute.

The quandary underscores how there’s no easy or obvious end game for the investigation, which last month reached its one-year anniversary. Though Mueller is expected to report his findings to Rosenstein, there’s no requirement that those conclusions be made public. And whatever he decides will unfold against the backdrop of a Justice Department watchdog report that reaffirmed department protocol against making detailed public statements about people who aren’t charged.

“Those are going to be the hard questions at the end of Mueller’s investigation: what is the nature of that report, and which if any parts are provided to Congress and the public,” said Georgetown law professor Marty Lederman, a former official in the Justice Department’s Office of Legal Counsel. “There’s just no way for us to know what if any parts of those reports can be made public or should be made public or will be made public.”

The investigation has hit a critical phase. A forthcoming decision by Trump and his lawyers on whether to sit for an interview with Mueller, who is examining whether the president sought to obstruct justice, could hasten the conclusion of the investigation with regard to the White House.

What happens next is unclear, though Mueller has been closely conferring along the way with Rosenstein, the No. 2 Justice Department official who appointed him special counsel.

If he decides a crime was committed, it’s theoretically possible he could seek a grand jury indictment, though that outcome is seen as highly questionable given a Justice Department legal opinion against charging a sitting president. Trump’s lawyers say Mueller’s team has indicated that it plans to follow that guidance.

Depending on his findings, he also could seek to name Trump as an unindicted co-conspirator in a case against other defendants, an aggressive step taken by the special prosecutor who investigated President Richard Nixon.

The regulations mandate that Mueller report his findings confidentially to Rosenstein, who would then decide how and what to share with Congress.

Lawmakers and the public would unquestionably demand access to any report, no matter the conclusion; a determination of wrongdoing would presumably be forwarded to Congress for possible impeachment proceedings, while a finding that no crime was committed would be trumpeted by Republicans as vindication for Trump.

Spokespeople for Mueller and the Justice Department declined to comment on the options under consideration.