Because we are factionalized, and using factions within the government to do our bidding. The parties are rackets, running protection and doling out goodies to their customers.
The party mentality is group think. People are part of the collective and sign away individuality for common cause when they join a party. Although many compromise with their values in the belief they will be heard later when the party candidate is elected. It never happens and they have compromised away their individuality. Party politics is responsible for the destruction of America. Only individualism and idealism will bring meaningful repair to our Republic.