Both parties have reached the point where their only objective is keeping the other party out of office. This means ignoring issues and simply attacking their opponent. Party faithful on both sides, fed a continuous diet of fear about what will happen if the other side wins, quit paying attention to actual issues. Intelligent voters get fed up with both sides and refuse to join either, leaving the nominating process to the most partisan and least informed voters. It's a race to the bottom. 

Meanwhile, by early next year we will be twenty trillion dollars in debt. Neither Trump nor Clinton are addressing this on any substantive level (it's an area Johnson excels in, but he's destroyed himself with his lack of foreign policy knowledge). We have to abolish both parties somehow and get intelligent and informed voters back in the game of choosing our candidates. Short of that we'll never fix the problem.