Defense lawyers had argued in court filings that the charges should be dismissed in part because marijuana’s Schedule I classification was arbitrary and unconstitutional. They asserted that the 10th Amendment barred the federal government from superseding state laws legalizing marijuana for medicinal use. Judge Mueller ruled that any adjustments to the law were better left to Congress. “This is not the court and this is not the time,” she said Wednesday, according to a report by The Associated Press. A written ruling will be issued by the end of the week.

The decision dismayed advocates of marijuana legalization.

“The medical benefits of cannabis are undeniable,” said Jeremy Norrie, a medical marijuana user in West Hollywood, Calif., who operates the Secret Cup, a cannabis trade show. “To keep it in the Schedule I classification is knowingly ignorant. It seems more to me that this judge wanted to avoid controversy and having to deal with the issue. We don’t see anywhere near the kind of public problems that the other drugs in Schedule I have.”

A spokesman for the D.E.A., Matthew R. Barden, said it would not comment until officials saw Judge Mueller’s written ruling.

The ruling is one of several indications that some resolution between federal and state marijuana laws may be approaching. In 2013, the Justice Department recommended that federal officials not target dispensaries, growers and patients who complied with state marijuana laws and had no links to cartels or interstate smuggling.

Moreover, the 2015 appropriations bill passed by Congress in December barred the Justice Department from spending money to interfere with any state’s efforts to carry out its medical marijuana laws. The Justice Department has countered that it can still prosecute violations of the federal marijuana ban and continue cases already in the courts.