  The HST proper motion (PM) measurements of the Clouds have severe
implications for their interaction history with the Milky Way (MW) and with
each other. The Clouds are likely on their first passage about the MW and the
SMC's orbit about the LMC is better described as quasi-periodic rather than
circular. Binary L/SMC orbits that satisfy observational constraints on their
mutual interaction history (e.g. the formation of the Magellanic Bridge during
a collision between the Clouds ~300 Myr ago) can be located within 1 sigma of
the mean PMs. However, these binary orbits are not co-located with the
Magellanic Stream (MS) when projected on the plane of the sky and the
line-of-sight velocity gradient along the LMC's orbit is significantly steeper
than that along the MS. These combined results ultimately rule out a purely
tidal origin for the MS: tides are ineffective without multiple pericentric
passages and can neither decrease the velocity gradient nor explain the offset
stream in a polar orbit configuration. Alternatively, ram pressure stripping of
an extended gaseous disk may naturally explain the deviation. The offset also
suggests that observations of the little-explored region between RA 21h and 23h
are crucial for characterizing the full extent of the MS.
