A severe lack of affordable housing has prompted Oregon lawmakers to consider chipping away at a 1970s law that made the state a national leader in leveraging land use policy to prevent suburban sprawl and conserve nature and agriculture. The so-called urban growth boundary, a sacred cow of Oregon’s liberal politics, helped to cement the state's green reputation and has been “extremely influential” in its development, said Megan Horst, an urban planning professor at Portland State University. The sole bill introduced by Democratic Gov. Tina Kotek during this year's short legislative session is a sweeping housing package aiming to jumpstart home construction by tweaking the 1973 law, which essentially drew a circle around cities to protect farmland, forests and nature from urban encroachment.