As the burgundy Cadillac races along the Mississippi highway, droplets of rain stipple the windshield and storm clouds signal rougher weather ahead. Dr. Tom Tucker, a circuit-riding abortion doctor, is on his car phone with a clinic. "How's it look?" he asks. There's a problem: it seems a large, angry man is raising hell in the parking lot while 40 antiabortion protesters picket the clinic. "This," says Tucker, his right hand slowly sliding down to touch the 9-mm Glock pistol wedged beside his seat, "is where I start to feel the tingle."
Tucker cranks up the CD player and blasts out...