PORTLAND — Oregon Republican Chairman Allen Alley says he’s resigning from a conservative political organization over a campaign mailing that included about 30 Democrats among its endorsements.

The Oregonian reports that Alley drew criticism from party members for the mailing from the Oregon Transformation Project. He said in a letter Sunday that he’d made a mistake in remaining as co-chair of the project.

The organization is largely supported by timber companies, including Stimson Lumber, and has been involved in Clackamas County and legislative races around the state.

The mailing was a “Women’s Voters Guide” that included recommendations from a panel of five women: two Republicans, two Democrats and one unaffiliated voter.

The recommendations heavily favored Republicans, but it included about 30 Democrats, a few in key competitive races.