Not too long ago political parties developed idea-based platforms, ratified them at their conventions, and then competed to win elections.
Redistricting (often called gerrymandering) in each state allowed the dominant party to pass laws and rules which virtually guaranteed that the party in power could hold on to that power.
The Republican Party gradually moved from advancing conservative ideas to using redistricting and filibusters to hold on to the power they had gained.
Party politics became a power-playing game focused on controlling election districts to maintain power and win races.
Republicans in Washington focused on stopping Democrats from accomplishing anything while Democrats focused on advancing social programs and debating among themselves the best way to do that.
Democrats therefore ended up focusing more on infighting between progressives and moderates than on developing idea-based platforms they all could rally around.
The July 16 issue of the Economist abandoned it’s nonpartisan policy and argues that in the U.S. only Democrats can save democracy… but to do so they must get their members all on the same page.
The fact is… Gerrymandered power could end up destroying our democracy..
Larry D. Lauer 
This is a frightening situation. It tilts politics far to the right and will keep it that way for years to come.