The Obama administration joined a federal judge Wednesday in urging Congress to end a racial disparity by equalizing prison sentences for dealing and using crack versus powdered cocaine.

"Jails are loaded with people who look like me," U.S. District Judge Reggie Walton, an African-American, told a Senate Judiciary subcommittee hearing.

Assistant Attorney General Lanny Breuer said the administration believes Congress' goal "should be to completely eliminate the disparity" between the two forms of cocaine. "A growing number of citizens view it as fundamentally unfair," Breuer testified.

It takes 100 times more powdered cocaine than crack cocaine to trigger the same harsh mandatory minimum sentences.

Sen. Dick Durbin, an Illinois Democrat who chairs the subcommittee, said, "Under current law, mere possession of five grams of crack -- the weight of five packets of sweetener -- carries the same sentence as distribution of half a kilogram of powder or 500 packets of sweetener."

Durbin said more than 81 percent of those convicted for crack offenses in 2007 were African-American, although only about 25 percent of crack cocaine users are African Americans.

Congress enacted the disparity during an epidemic of crack cocaine in the 1980s, but the senator said lawmakers erred in assuming that violence would be greater among those using crack.

Breuer said the best way to deal with violence is to severely punish anyone who commits a violent offense, regardless of the drug involved.

"This administration believes our criminal laws should be tough, smart, fair," Breuer said, but also should "promote public trust and confidence in the criminal justice system."

Walton said, "We were mistaken" to enact the disparity. "There's no greater violence in cases before me."

He added that jurors have expressed an unwillingness to serve in crack cocaine cases because of the disparity.

President Barack Obama had called for such a change while campaigning for the White House.

Breuer said the government should focus on punishing drug trafficking networks, like the cartels wreaking havoc in Mexico, and those whose crimes include acts of violence.

The Obama administration is also seeking to increase drug treatment, as well as rehabilitation programs for felons after they're released from prison.

Miami's police chief, John Timoney, also favored ending the disparity, commenting, "It's the same drug. It's just manufactured differently."

Cedric Parker, of Alton, Ill., said his sister, Eugenia Jennings, is serving nearly 22 years for trading crack cocaine for designer clothes. If she had been trading powder cocaine, the sentence would have been less than half of the time.

"She would be getting ready to come home, probably already in the halfway house. But, because she was sentenced for crack cocaine she will not be released from prison until 2019," Parker testified.

While politicians often support laws lengthening prison terms for various crimes, it is rarer to try to reduce sentences, in part out of concern they may appear soft on crime. But recently, some states have been moving on their own to temper long-standing "get tough" laws.

In New York last month, state leaders reached an agreement to repeal the last vestiges of the Rockefeller drug laws, once seen as the harshest in the nation. Kentucky enacted changes that would put more addicts in treatment, and fewer behind bars.

The Justice Department is working on recommendations for a new set of sentences for cocaine, and Breuer urged Congress to overhaul the current law, written in 1986 at the height of public concern about crack use.

Since then, Breuer argued, prosecutors' views of crack cocaine have evolved to a more "refined understanding" of crack and powdered cocaine usage.

He also suggested that until such changes are made, federal prosecutors may encourage judges to use their discretion to depart from the current sentencing guidelines. Such departures are rare in the federal courts.