HARTFORD, Conn. — A Connecticut lawyer is hoping his arguments in a drug case eventually are used by attorneys across the country to fight marijuana charges and bans on pot possession.

Aaron Romano says many state laws criminalizing marijuana were based on the federal Marihuana Tax Act of 1937, which essentially criminalized marijuana by imposing harsh financial penalties. He argues the federal law was rooted in racism and bigotry against blacks and Mexicans and therefore was unconstitutional, as are the state bans based on the law including Connecticut’s.

“It was racially motivated and states just adopted it wholesale,” said Romano, a Bloomfield attorney who also is legal counsel for the state chapter of the National Organization for Reform of Marijuana Laws. “With the growing awareness of cannabis’ health benefits … at this point there is no reason to maintain its illegal status.”

The prosecutor, Russell Zentner, declined to comment, while at least one drug law expert doesn’t believe such an argument would be successful.

Romano made the unusual argument Tuesday in a motion to dismiss marijuana possession and probation violation charges against his client, William Bradley. The Clinton resident was caught with nearly a pound of marijuana in January while on probation for a previous marijuana conviction. He is detained while awaiting trial because he can’t post $150,000 bail.

Pretrial discussions in Bradley’s case are set for Tuesday in Middletown Superior Court.

Romano said his arguments are different than past, unsuccessful challenges to marijuana bans because his case focuses on the discriminatory origins of such prohibitions, instead of how the laws have resulted in minorities being arrested at disproportionate rates compared with whites.

Romano’s motion to dismiss the charges against Bradley cites a variety of publications in saying century-old pot bans were rooted in discrimination. The first bans were enacted in the early 1900s in states with large numbers of migrant workers from Mexico, where marijuana use was more common, and were designed to make the workers vulnerable to prosecution, the motion says.

Romano also said the 1937 federal law was successfully pushed by Harry Anslinger, the first commissioner of the Treasury Department’s Federal Bureau of Narcotics.

Anslinger was driven by racial prejudice, the motion says, and he claimed that many violent crimes committed by Latinos and blacks were linked to their marijuana use. Anslinger also said marijuana made black men lust for white women, according to the motion. Many medical professionals at the time opposed the 1937 law and said there was no evidence linking marijuana and crime, the motion says.

In 1970, a new federal drug law placed marijuana in the most restrictive category of drugs after the 1937 act had been ruled unconstitutional. Many state laws are now in conflict with federal law. Recreational use of pot is legal in eight states and Washington, D.C., while more than half of states allow medical marijuana.

Robert Mikos, a professor at Vanderbilt Law School, said similar challenges to marijuana prohibition have been dismissed by the courts.

Mikos said it would be nearly impossible to get a judge to rule the 1937 law unconstitutional, partly because there were legitimate concerns about marijuana at the time including the health effects and people switching to pot while the prohibition on alcohol was still in place.

“It is extremely unlikely, almost to the point of 0 percent probability, that such an argument would prevail in court,” he said.