By Amy Goldstein @ WashingtonPost.com, July 7

The judges of the marbled appellate courthouse in the heart of New Orleans once upended civil rights law, issuing rulings that propelled desegregation. This summer, they could upend health-care law and with it, the roiling politics of health care in Congress, the White House and the 2020 campaigns.

On Tuesday, the Trump administration and 18 Republican-led states will face off against a score of Democratic-led states over the constitutionality of the Affordable Care Act — the sprawling law the Supreme Court has upheld twice but a federal district judge in Texas ruled invalid late last year.

If the U.S. Court of Appeals for the 5th Circuit hearing these arguments agrees with the lower court, the “win” for Republicans, who have sought for nearly a decade to ditch the ACA, could perversely cause the GOP the greatest trouble, according to analysts from both parties [....]