A D.C. Superior Court judge put Umoja Party leader Mark Thompson on probation yesterday for three years for failing to pay District income taxes, telling the political activist to build a "track record of someone who really is responsible."

Thompson, who admitted that he did not pay taxes for years, said he had "vacillated" for political reasons about the justice of paying taxes, but added, "I am probably as guilty of procrastination as anything."

The statehood advocate said he feels "the greatest remorse" for not bearing his share of the cost of District services.

"I apologize to you and to the citizens of the District of Columbia," Thompson told Judge Cheryl M. Long.

Thompson also said he felt that he had been punished by publicity. "This has been a very embarrassing ordeal for me," he said.

Long ordered a one-year jail term for Thompson, 32, who is serving two years' probation for assaulting his ex-wife. But the judge suspended the sentence and said Thompson can remain free if he pays $100 a month toward $3,565.82 in back taxes, files future tax returns on time and otherwise obeys the law.

"There really is no ultimate excuse," the judge told him.

Thompson pleaded guilty in September to two misdemeanor tax charges, admitting that he did not file a tax return or pay D.C. income taxes in 1995. In return, D.C. authorities dropped identical charges for 1996 and 1997. Thompson agreed to pay back taxes for the years 1995 to 1998.

In an interview with The Washington Post last year, Thompson said he had not filed federal or local taxes for six years beginning in 1992. The issue emerged during a 1998 divorce hearing when a Superior Court judge said Thompson, who was far behind in child support payments, had failed to provide needed financial records.

D.C. prosecutor Nan Reiner said in court yesterday that the sometime radio announcer "flagrantly thumbed his nose" at the tax system. She said the case "cries out for someone to say, 'Mr. Thompson, you should have known better.' "

Even after Thompson pleaded guilty, Reiner said, the District felt as though it was "pulling teeth" to get Thompson to produce his returns and fulfill his obligations. Thompson filed his 1998 return 30 minutes before yesterday's hearing.