Why we are to blame for our broken politics?

As recently as 1994, more than one-third of Republicans were identified as more liberal than the average Democrat. That number is 5% today. Ditto Democrats, where 30% were more conservative than the average Republican in 1994 while just 3% are today.

You can see the parting of ways when you dig into the 10 value questions on which Pew bases these broader numbers. Consider:
* 65% of Republicans agree with the idea that "poor people have it easy because they can get government benefits without doing anything in return." Just 18% of Democrats say the same.
* 75% of Republicans say "blacks who can't get ahead in this country are mostly responsible for their own condition," while 28% of Democrats agree with that sentiment.
* 53% of Republicans think "the best way to ensure peace is through military strength," while only 13% of Democrats think the same.
In those 10 value questions -- which Pew has been asking since 1994 -- the average gap between Democrats and Republicans is now 36 percentage points. It was just 15 percentage points in 1994.
Democrats are now more consistently liberal. Republicans are now more consistently conservative. And that puts them further away from one another than ever before.
There are lots of facts to explain this increased polarization in the country. Self-sorting means we tend to live around people who agree with us all the time. The fracturing of the mainstream media has allowed people to only consume news and information that comports with their pre-existing beliefs.
There's also been a rise in tribalism,this is one of the major reasons -- using the party you belong to to define not only how you see yourself but also how you see every issue -- in the last decade-plus.
here is a graph that explains this.