NOTES
There is one more possibility - a retrograde orbit. In this case, the satellite is always slowing the primary's rotation, no matter whether it's below, at, or above the synchronous orbit radius, and the primary's tides are always slowing the satellites orbit (dropping it into a lower orbit with less angular momentum), and the satellite's tides are always slowing the primary's rotation. The destruction of the satellite by a collision or by tidal disruption is inevitable.