Maryland Lt. Gov. Anthony G. Brown. (Photo by Astrid Riecken For The Washington Post)

Maryland Lt. Gov. Anthony G. Brown, a leading Democratic candidate for governor, on Monday called the state’s marijuana laws “costly, ineffective and racially biased” in a letter in which he outlined his reasons for supporting decriminalization of small amounts of the drug.

Brown had previously said he is willing to support legislation that imposes civil fines — rather than criminal sanctions including jail time — for possession of small amounts of marijuana. But he offered some of the most extensive comments on the issue in the letter made public by his office late Monday.

“I support the decriminalization of marijuana because I believe in strong communities where safety — and not just the appearance of being tough on crime — comes first,” Brown wrote. “Decriminalization isn’t about encouraging drug use; it’s about putting our resources in the places where they’ll do the most good. It’s about helping young people who are caught with small amounts of marijuana find a better way forward instead of putting them through the revolving door of our justice system.”

The letter came in response to a proposal earlier in the day by Del. Heather R. Mizeur (D-Montgomery), a rival candidate for governor. Mizeur had requested that both Brown and Attorney General Douglas F. Gansler (D) join her in testifying for a bill she is sponsoring during the current 90-day session to decriminalize marijuana.

Brown wrote that her bill is “a welcome part of this debate,” but he did not answer her directly in his letter. Instead, Brown spent most of the letter explaining his rationale for supporting the idea of decriminalization.

In 2010, he said, African Americans were almost three times as likely to be arrested for marijuana possession as their white counterparts. And, he said, black Marylanders account for 58 percent of all marijuana possession arrests but only 30 percent of the population. Usage rates are almost identical among blacks and whites, he said.

“An arrest for possession has an in­cred­ibly negative impact on that person’s life, often creating problems finding employment or even a place to live,” Brown wrote. “Equally distressing is how ineffective and costly marijuana laws are.”

Brown wrote that four years ago, Maryland spent more than $55.3 million on police costs alone while enforcing the law.

“These are resources that could have been better spent fighting violent crime throughout our state, or on substance abuse treatment that could help the cycle of use and dependency,” Brown wrote.

He said that any efforts to decriminalize the drug “must be coupled with an investment to educate young people about the hazards of marijuana use.”