WASHINGTON — Investigators for the special counsel spent months trying to get answers from President Trump: what he knew about a meeting between senior campaign aides and Russians; about changes to the Republican Party platform making it more Russia-friendly; about his associates’ outreach to WikiLeaks as it prepared to publish Democratic emails stolen by Russian hackers.

After months of resistance, his lawyers finally turned over written answers in November to those questions and others. But the public has not seen them.

Now, the question of whether they become part of the available history of Russia’s 2016 election interference and its aftermath — along with whatever else the special counsel, Robert S. Mueller III, may have gathered — turns on Attorney General William P. Barr. Since Mr. Mueller submitted a nearly 400-page report on his investigation two weeks ago, Mr. Barr, his aides and other law enforcement officials have been reviewing it to determine which portions to provide to lawmakers and the public — and what to black out.

Democrats in Congress, who have demanded to see the entire document, have expressed growing impatience with Mr. Barr. And members of Mr. Mueller’s team have told associates that Mr. Barr failed to adequately convey findings that were damaging to Mr. Trump in a letter he sent to Congress two weeks ago laying out their chief conclusions.