In a political system CONTROLLED by TWO PARTIES as is ours, every voting decision is subject to a BINARY STANDARD: If not Y then X.
Candidates are never effectively measured against anything MORE WORTHY than their opposition-party rival.
This system assures both Parties that voters WILL NOT effectively hold their candidates accountable to the principles of their Constitution, the stated platform of their party, standards of decency, civility or (lately) even lawful behavior. ...
In this manor, CONTROL of the political process by two established parties protects the Ruling-Class Establishment seated by those parties.
This is the reason we cannot pursue effective reform through Elections alone. Our power as voters is not even used to demand lawful behavior of our office-holders, never mind standards of Constitutional governance as long as the only measure of acceptability is "Better than X."
Real reform must take the form of bringing our power back home - Convening the states under Article V in order to bring forth authentic reform proposals not possible any other way.