“O.S.C.’s guidance was not intended to prevent all discussions of impeachment in the federal workplace,” the revised guidance said, adding: “Merely discussing impeachment, without advocating for or against its use against such a candidate, is not political activity. For example, two employees may discuss whether reported conduct by the president warrants impeachment and express an opinion about whether the president should be impeached without engaging in political activity.”

However, it said, employees may not display in their offices posters that call for the impeachment of Mr. Trump, or place a “Don’t Impeach Trump” bumper sticker on a government-owned vehicle.

[Read the clarification and the original Hatch Act guidance issued this week.]

The revised guidance also said that some uses of the “resist” slogan remained permissible, so long as it was being used in relation to an issue rather than to Mr. Trump. It offered, as acceptable uses of the slogan because the context was not a political campaign, the examples #ResistHate and #ResistKavanaugh.

The clarification came as the agency issued findings that six members of the Trump administration had violated the Hatch Act for using Mr. Trump’s Make America Great Again slogan in Twitter posts, based on its reasoning that the slogan amounted to endorsing his campaign. At the same time, the office cleared Mick Mulvaney, the director of the Office of Management and Budget, for using the term “MAGAnomics” in an opinion column, ruling that its context was Mr. Trump’s economic program rather than his 2020 re-election effort.

Against that backdrop, not all critics of the guidance initially issued this week were mollified. Among them, Austin Evers, the executive director of American Oversight, a nonpartisan watchdog group, said in a statement that the rules remained unclear and called on the office to withdraw all the guidance and start over.