U.S. states are trying to capture corporate income taxes lost to offshore havens, wary of companies exploiting rules that let them channel cash abroad and weary of congressional inaction.

Oregon enacted a bill for the 2014 tax year identifying 39 countries and territories as corporate shelters a decade after Montana passed the first such law. The Democrat-controlled Maine legislature gave initial approval this week to similar legislation over Republican objections that it was "anti-business," and states including Minnesota and Rhode Island are considering or studying such measures.

States have taken the lead on issues that a paralyzed Congress can't or won't address, such as raising the minimum wage and restricting guns. Now, they're tackling international tax rules. Supporters say that besides generating additional money for public services, laws targeting tax havens help small businesses that can't avoid the levies as multinationals can.