Oregon's top state senator is calling for business, union and political leaders to negotiate a plan to withdraw a series of contentious ballot measures slated for next year's election.

Senate President Peter Courtney warned Monday that "Oregon is on the verge of its own civil war" pitting the state's most powerful interests against each other.

The Salem Democrat says compromise is needed to avoid "the bloodiest day in Oregon political history."

A group backed largely by public-employee unions has proposed ballot measures to significantly increase taxes for corporations. Other groups are looking to raise the minimum wage.

Meanwhile, business groups are considering a ballot measure to weaken union rights.

Courtney spoke at the annual Oregon Leadership Summit in Portland, which brings together the state's business and civic leaders.