The American Civil Liberties Union demanded Thursday that Portland International Airport accept terminal advertising against legislation to increase logging on federal forests.
Oregon ACLU director Dave Fidanque said the Oregon Constitution prohibits government censorship of speech, including political speech.
"We think the law is very clear in Oregon," he said. "Public agencies cannot discriminate based on content of expression when they open up their places for advertising."
He added that activists have been winning a similar fight with Tri-Met over ads the Karuk tribe wants to place on Portland buses as part of a campaign to remove dams from the Klamath River to help salmon. The last ruling requiring the buses to carry the ads was appealed to the Oregon Supreme Court, where a ruling is pending.
Airport spokeswoman Martha Richmond says the airport has the power under state and federal law to restrict the placement of ads on religious and political issues, in order to maintain neutrality.
She added political and religious speech is allowed in specific locations under a permit program.
The logging ad was submitted by Oregon Wild as part of a national campaign to defeat a bill in Congress to increase logging on federal forests, particularly the so-called O&C lands in Western Oregon.
O&C lands are a patchwork of federal forest lands that once provided generous revenues to rural counties. But after environmental restrictions cut logging in the 1990s, counties have struggled to pay for basic services.
The ad against expanded logging is a blowup of a postcard depicting a hillside where all the trees have been cut and hauled away, saying, "Welcome to Oregon, Home of the Clearcut!"
Conservation groups have been campaigning against a House bill that would set logging quotas for national forests and give states more say over forest management. It includes a provision to turn over 1 million acres of the so-called O&C lands to a state-appointed trust to be managed primarily for timber production and revenues for rural timber counties.
Conservation groups contend that by putting the lands under the Oregon Forest Practices Act, the bill would allow large clearcuts, which are currently allowed on private lands.
Rep. Peter DeFazio, D-Ore., is chief sponsor of the O&C bill. He counters that the bill contains a variety of protections that go beyond the Oregon law, such as expanding no-logging zones along streams and limiting overall timber production.
The bill is scheduled for a vote Friday in the House. President Obama has threatened to veto it if it passes the Senate.