BOSTON - A Greenfield man won on his day in court when a federal appeals panel ruled that the Massachusetts Bay Transportation Authority violated his free speech rights by refusing to display ads from a group he founded that wants to change marijuana laws.

The 1st U.S. Circuit Court of Appeals found that the authority's refusal to display three advertisements submitted by the nonprofit group Change the Climate violated the First Amendment because it was based on officials' disapproval of the views expressed in the ads and not made on a content-neutral basis.

The ads were rejected four years ago, with the authority claiming they encouraged children to smoke marijuana. Officials argued that the authority has the right to protect riders from offensive messages or advertisements that "promote the use of illegal goods or services."

Joseph White of Greenfield, who founded Change the Climate in 1999, contends that the ads do not promote marijuana use by children, but instead seek to stimulate debate about current marijuana laws.

"Teenagers have easy access to marijuana in just about every community in Massachusetts and they have a much harder time getting alcohol and tobacco because it's regulated by adults," White said. "I think if adults are serious about keeping marijuana away from our kids that we would regulate and control it like we do alcohol and tobacco.

"In particular as parents, we're concerned that we are arresting our children in significant numbers and we're doing a lot more harm in that than probably marijuana does to them," White said.

The appeals court found that the MBTA, a quasi-government agency, does not have the right to turn down advertisements based on the personal viewpoint of its executives.

"MBTA advertising space is literally a billboard for the expression of opinions to citizens at large. As a government agency, they shouldn't have the right to pick and choose what opinions they allow to be advertised," Harvey Schwartz, an attorney for the Greenfield-based advocacy group argued.

The court did find, however, that the MBTA advertising space does not constitute a public forum, as had been claimed by Change the Climate.

"The Supreme Court has repeatedly held that the government must have an affirmative intent to create a public forum in order for a designated public forum to arise," the justices wrote.

The advertisements proposed by Change the Climate question current marijuana laws and penalties for people arrested on minor possession charges.

"I've got three great kids," reads one ad. "I love them more than anything. I don't want them to smoke pot. But I know jail is a lot more dangerous than smoking pot."

An MBTA spokesman said Tuesday that their attorneys were reviewing the court's ruling and had no immediate comment.

The MBTA provides public transportation to approximately 1.2 million customers every day on subways, trains, buses and ferries. Up to 60,000 Boston public school students use the MBTA to get to classes.

As dictated by law, the MBTA uses its 40,000 advertising spaces on buses, trains, trolley and station platforms to generate revenue beyond that raised by fares.

Over the years, the MBTA has received a number of complaints from its riders about advertisements and in the five-year period before the lawsuit was filed by Change the Climate, the MBTA rejected at least 17 advertisements barred by its ad policy, including some depicting violence, profanity and tobacco products. They did, however, allow advertising for alcoholic beverages and for movies with sexual themes.

The 1st Circuit found that although the MBTA's advertising guidelines are "viewpoint neutral" and constitutional, its rejection of the three Change the Climate ads was unreasonable and amounted to "viewpoint discrimination."

"Inherent in the MBTA's position is its recognition that, save for the risk of inducing juveniles to smoke marijuana, the refusal to run these advertisements for an adult audience would be viewpoint discrimination. That conclusion is essentially conceded in the MBTA's briefs," the justices wrote.

"There is direct evidence through statements made by MBTA officials that the reason for rejecting the advertisements was actually a distaste for Change the Climate's viewpoint," they added.

"This suspicion of viewpoint discrimination is deepened by the fact that the MBTA has run a number of ads promoting alcohol that are clearly more appealing to juveniles than the ads here," the court said.

White said he plans to begin raising money for the ads immediately. When the group first proposed the ads four years ago, it planned to spend $50,000 on the advertising campaign, White said.

In a separate matter joined with the Change the Climate case at the appellate level, the court said the MBTA did have the right to reject ads from the Church with the Good News because that group's ads were demeaning or disparaging toward other religions.

In one case, the church's advertisements stated that "Satan set up over a thousand false religions in the world ... There is only one true religion. All the rest are false."

Other advertisements by the Good News church disparaged specific religious groups by name.