Redistricting has divided the various political district into overwhelmingly Democratic or Republican by various demographic factors. Where in the past, winning politicians needed to appeal to some independent voters, not so much anymore. Now, if a ham sandwich ran for office with the backing of the correct party, it would win.
In a “democratic” district this means that almost the only people voting or the vast majority were Democrats. And will vote for the candidate the “party” (or sometimes their union) tells them to vote for.
The new Democratic party is more shaped by activist and progressives. Currently there are 5 “Democratic Party” litmus tests: (1) Hate Trump, (2) Pro-Abortion, (3) Anti-2nd Amendment & firearms, (4) LGQT...etc.., (5) Stop Racism & social justice through quotas on police/judicial activity.
A long, long time ago, when I was young and dumb a wise friend told me that the only good Democrat was a dead Democrat. I argued that was nonsense. He asked me to name a good Democrat, I admired. All the ones I had admired were dead, I could not name a single living Democrat I really respected.
The Democratic party has worked for decades to marginalize its appeal to the general public.
What they’ve done is make people too apathetic to stop them.
It’s indeed the “Triumph of the Will”.