Long-shot legal challenge could end Obamacare during the 2020 campaign

Obamacare’s future will once again be at stake Tuesday when a federal appeals court considers a Trump-backed lawsuit aimed at scrapping the health care law in the heat of the 2020 election cycle.

The court will hear oral arguments on whether the Affordable Care Act is no longer valid after Congress eliminated the tax penalty for not purchasing health insurance. The lawsuit, brought by 18 Republican-led states, could jeopardize health care coverage for more than 20 million people insured through the 2010 health care law, eliminate insurance protections for preexisting...