PORTLAND – A federal judge has ruled that a man arrested on a firearms charge outside the Bush family estate last year cannot be forced to take medication to make him mentally competent to stand trial.

U.S. District Court Judge Gene Carter ruled that Theodore Miller has a constitutional right to refuse to be medicated against his will, even though he has been found mentally incompetent.

Carter’s ruling is the first in Maine and one of the first in the country to rely on a U.S. Supreme Court decision last June that won praise from mental health advocates.

Carter ordered that Miller continue to be held in the medical wing of the Federal Correctional Institution in Butner, N.C., where his mental state will be tested periodically until he is able to assist in his defense. Doctors say Miller will not improve without medication.

“The government has shown no important interest in bringing this defendant to trial in the near future,” Carter wrote. “Such a showing is required to permit the overriding of [Miller’s] due process right to avoid such compelled medication.”

In his decision, Carter relied on a landmark Supreme Court decision, Sell v. United States, which was decided in June. The court ruled that for involuntary medication to be acceptable, the government must prove that it is medically necessary and would not interfere with the defendant’s ability to defend himself.

Carter’s ruling puts Miller in legal limbo, even though he got the ruling he wanted.

If found guilty of possessing a firearm after being committed to a mental institution, Miller would face only 18 months to two years in prison, said his lawyer, Bruce Merrill. He has already been in custody since Sept. 30, 2002.

“It’s a tough, tough position,” Merrill said. “He could spend more time in civil commitment than he would if he were convicted of the crime.”

According to court documents, Miller presented himself to Secret Service agents at the Walker’s Point compound in Kennebunkport on Sept. 30, 2002, four days before President George W. Bush was scheduled to arrive for a weekend visit.

The agent said Miller asked for help from the president and the agents, and said he was being followed by strangers and needed help with a disability claim.

Miller was found to have two boxes of shotgun shells in his car, and said they were for a firearm he kept in a storage locker in Bangor with 19 other guns. He told them that he had been involuntarily committed to the mental ward of a New Jersey hospital during the previous year for 40 days. Involuntary commitment, like a felony conviction, makes it a crime to have a gun under federal law.

While in custody, a government psychologist reported that Miller had “delusional disorder,” lacked a “rational understanding” of the court proceedings and was unable to assist in his own defense. He was ruled incompetent on March 3.

Miller was transferred to the federal prison in North Carolina, where doctors said he required psychotropic medication to treat his mental disorder. He refused to take the drugs.

The Sell v. United States decision has been praised by mental health advocates who say that in the past, defendants have been made technically competent with forced medication, but still were not capable of getting a fair trial.

The side effects of some medications could make a defendant look cold and impassive to a jury, or make a client too dull-witted to assist his lawyer, said Ron Honberg, legal director of the National Alliance for the Mentally Ill.

Cases such as Miller’s raise difficult legal issues that courts will face more often since the Sell decision, Honberg said.

“There has never been a comfortable marriage between the law and psychiatry,” he said.