Car doesn't start?

2000 Ford Focus will not start. It doesn't try to turn over. Nothing happens when I turn the ignition key. There is a single click at the starter motor, but nothing happens. I tried jumping the battery, replaced the starter, and replaced the starter relay. All the electronics work with the ingnition key turned on. It almost sounds like the clutch is not ingaging when trying to start, but I know the clutch is working cause I can start the car by pushing and popping the clutch and shift gears while driving.