Personal, not Principle

The Republican Congress didn’t reject universal gun background checks on principle, but because, 

The magnitude, intensity, and obsession of rightist hatred of the president is unprecedented in the history of American politics because it has poisoned the ability of Republican leaders in Congress to work in good faith with a twice-elected American president.

This GOP leadership’s fear and sanction of rightist hatred towards the president foments a near total obstruction against anything the president and Democrats propose, creates a near total gridlock of government in Washington and demonstrates a contempt for long-held notions of American civic life that have traditionally been accepted by all major political parties.

That comes from that leftist rag the “Hill“.