Assuming delegates wanted to maximize their state’s vote share, we examine which principles of apportionment were coalitionally stable at the U.S. Constitutional Convention of 1787.  We do this by comparing vote shares of all the principals considered at the U.S. Constitutional Convention of 1787, both for a unicameral legislature and a bicameral legislature, separately. This allows us to ask whether the apportionment principle adopted was in equilibrium among the principles considered, allows us to identify the principles which dominate the one appearing in the Constitution, and provides examples of vote cycling.