WASHINGTON -- Republican Alan L. Keyes says he will run for the U.S. Senate seat held by Barbara A. Mikulski.

Keyes says the political environment is more favorable to his candidacy now than in 1988, when he lost to incumbent Sen. Paul S. Sarbanes, D-Md., by 62 to 38 percent.

"There's a lot more of a sense that a change is really needed,"

Keyes said yesterday, adding: "I think there's a general issue -- which is a perception that a lot of people have, rightly, that the government is not working any more."

Should he capture the GOP nomination, Keyes, a conservative, would face Mikulski, a liberal Democrat, in a state where Democrats hold a wide lead in voter registration. But the number of registered Republicans is increasing and there are Democrats who are "not any longer Democrats in the way they think and the way they vote," he said.

Keyes, of Darnestown in Montgomery County, heads a private advocacy group in Washington, Citizens Against Government Waste.

He quietly filed a statement of candidacy last week with federal officials and confirmed his plans yesterday. He intends to formally announce his candidacy Nov. 20 at the American Legion Hall in Towson.

Other Republicans running for the Senate are Harford County State's Attorney Joseph I. Cassilly; Stuart W. Hopkins, a member of the Republican Central Committee of Caroline County; and Eugene Robert Zarwell of Gambrills. The party primary is March 3.

Mikulski, a first-term senator, had $900,000 in the bank for next year's campaign as of June 30. Keyes said he hopes to raise $1.5 million to $2 million.