George Sutherland, Columbia Railway Gas Electric Company v…
“ The effect of the act of 1917 is to convert that which we have held to be a covenant into a condition subsequent and to impose as a penalty for its violation the forfeiture of an extensive and valuable property. It requires no argument to demonstrate that this constitutes an impairment of the contract here involved, in violation of the Constitution. The impairment of a contract may consist in increasing its burdens as well as in diminishing its efficiency. ”
