A showdown vote on a state income tax, three years in the making, could take place in the legislature today, if backers are able to overcome opposition by a handful of lawmakers to a six-month sales tax increase.

The legislative action is expected to take place against a noisy backdrop of anti-tax protesters honking car horns and waving placards. They plan to rally 5:30 a.m.-1 p.m., organized by radio talk-show host Steve Gill.