I like this graph the best, but read the entire thing for yourself:
The grassroots of the major parties are weak. Their abdication only makes more room for initiative peddlers, media, political consultants and the special interests that fund the whole enterprise.
The solution is more participation based in the notion of people coming together for the common good. The party rank-and-file can and need to resolve the current crisis by holding precinct nominating conventions and endorsing Ranked Choice Voting. The alternative is continued irrelevance.