1997 Volkswagen Jetta Wobble once per tire revolution

My wife has been noticing a weird shaking for several weeks. We parked it for a week while on a trip, and I took it today to see if I noticed it too. The right front tire was flat, so I inflated it with a bike pump.

Pulling out of the driveway I could feel a little wobble, then moving slowly down our block, the wheel would shift to the left slightly, then return to straight, once every second or two (roughly once per revolution). I parked it, and felt around the tires looking for any obvious problems (like a big nail). Can't see anything obvious.