First Guilty Plea Is Set in Jan. 6 Police Assault Case

But even as the guilty pleas continue to increase, only six Capitol rioters have been sentenced, and none have been given serious prison terms.

One woman, an Indiana grandmother, was sentenced in June to probation with no time in prison; a married couple from Virginia were ordered this week to serve brief stints of home confinement; and two men, who were kept in custody for months as their cases moved through the courts, were sentenced to time served.

Only one person, Paul Hodgkins, a Florida crane operator who admitted to breaching the Senate floor and obstructing the certification of the Electoral College vote, has been given any time in prison. But the eight-month term that Mr. Hodgkins received was far less than the 20-year maximum possible under the law.

The roughly three- to four-year sentence that prosecutors have proposed for Mr. Fairlamb is substantially lower than the seven to eight years they had quietly recommended in early negotiations with other defendants charged with assaulting the police, according to their lawyers. If the government’s suggestion in Mr. Fairlamb’s case is accepted by the presiding judge, Royce C. Lamberth, it would mark the most significant sentence prosecutors have won to date.

The issue of how severely, or leniently, to treat those charged in the riot has only grown sharper as more Capitol cases move toward resolution. One suspect, a Dallas man charged with storming the building and facing off with officers inside, has argued, for example, that prosecutors have been unduly harsh to the Capitol defendants compared to how they treated leftist activists accused of rioting last year at a federal courthouse in Portland, Ore.

By contrast, the chief federal judge in Washington, Beryl A. Howell, has questioned whether the government has been too generous with Capitol rioters. In an unusual exchange last month, Judge Howell asked prosecutors whether it was appropriate to permit those involved in “terrorizing members of Congress” to plead guilty to low-level misdemeanor charges.

Judge Howell’s questions came during a plea hearing for Jack Jesse Griffith, a Tennessee man who had admitted to a single count of illegally protesting at the Capitol. The charge carries a maximum sentence of six months in prison, and Judge Howell wondered whether that was sufficient for a man who, she said, joined a mob that broke into the building and stopped “a constitutionally mandated duty of the Congress.”

“Does the government, in agreeing to the petty offense in this case, have any concern about deterrence?” she asked.