Maryland will get a new weapon in the war on drugs today when a new state law takes effect, and Virginia will begin an experiment to see how youthful offenders react to a military-style prison boot camp.

The Maryland law, the centerpiece of Gov. William Donald Schaefer's anti-drug initiative in 1990, would allow the suspension or revocation of 150 types of business and professional licenses held by people convicted of drug offenses.

Schaefer hailed the law as an assault on the "demand" side of the illegal drug trade in Maryland.

State regulators could take away the licenses of people in disparate fields, such as electricians, librarians and commercial drivers, after a drug conviction. However, a judge could overrule the decision if he finds no connection between drugs and the occupation.

The Maryland law is one of a dozen that go into effect today instead of the traditional July 1 starting date.

Lt. Gov. Melvin A. Steinberg said the licensing bill is important because it allows authorities to focus on the cocaine abuser.

"The profile of a cocaine abuser is a white male under 40 with a job. People don't understand that," Steinberg said.

Civil libertarians, however, have decried the broad nature of the licensing law, questioning whether any connection can be made between the use of drugs and the jobs of individuals.

Stuart Comstock-Gay, head of the American Civil Liberties Union in Maryland, said legislators are overzealous. "When it comes to the drug war, anything goes," Comstock-Gay said.

A related law going into effect today is aimed at drug couriers. The measure will require a distinctive registration plate on automobiles rented in Maryland. Police say rental vehicles often are used to transport drugs, and the identification will aid them in tracking drug shipments.

Among other Maryland laws going into effect today are measures that will:

Prohibit salesclerks from writing down the credit card number of a customer when the card is used as identification in writing a check. Supporters said the practice had led to credit card fraud by making the numbers and expiration dates on the cards too widely available. Clerks may still ask to see a credit card but may not record the numbers.

Require builders to state in writing whether the houses they sell are covered by warranties. The measure does not require that warranties be offered, but backers of the law say it will encourage builders to offer the coverage.

Authorize Frederick County to charge "impact" fees to developers to offset the cost of roads and utilities needed to support new construction.

Require that voter registration information be available at public schools, community colleges and other state institutions of higher education.

In Virginia, perhaps the most notable measure going into effect today is the trial program that will allow younger first-time criminals convicted of nonviolent felonies, such as larceny, burglary or minor drug crimes, to go to a camp instead of a traditional prison.

The program, open on an optional basis to convicts ages 18 to 24, features intensive supervision for rehabilitation and training, patterned after a military boot camp. It is based at Southampton Correctional Center in Southside Virginia, and has room for 100 inmates. The inmates would go to the camp for 90 days, then be placed on parole for at least a year.

Legislation authorizing the camp was sponsored by Del. Vincent F. Callahan Jr. (R-McLean) and is similar to a proposal advanced by J. Marshall Coleman, the unsuccessful Republican nominee for governor in 1989. Maryland opened a prison boot camp in 1990 and expects to "graduate" its first class on Jan. 17.

Other new Virginia laws will:

Grant a 10 percent tax credit to businesses for purchasing machinery used to make goods with recycled materials.

Require lending institutions to provide notices to customers informing them of how interest costs are calculated if they decide to prepay loans.

Require that agents for athletes get a license from the state Department of Commerce before doing business. If they don't have liability insurance, agents also must obtain a $100,000 surety bond.

Give a tax credit to landlords who reduce rent by at least 15 percent for disabled tenants or tenants over age 65. Landlords can take the tax credit for half the amount of the total rent reduction. The tax credit program is regulated by the Virginia Housing Development Authority.

Increase the minimum taxable wage base from $7,000 to $8,000. Also, the minimum state unemployment benefit is increasing from $56 a week to $60, the maximum benefit from $176 to $198.

The Associated Press contributed to this report.