Informative read: NYT Article By Amanda Taub
“That helps explain why Mr. Trump’s support among Republican voters remains quite high, even though the first few months of his presidency have been plagued by scandals and political setbacks, and even though his overall national approval ratings are now very low. He has been careful to recast every potential scandal and policy struggle as a battle against the Democrats and other outside groups.”
The article does a nice job of describing the sources of bipartisanship as tribal self-expression, among others.
Here is a second article also from the NYT, published in January: Are You Wedded to Your Party?