A federal judge in the US state of Texas has ruled that a key part of the Affordable Care Act (ACA), better known as Obamacare, is unconstitutional.
A coalition of 20 states argued the entire law had been invalidated by a change in tax rules last year which eliminated a penalty for not having health insurance.
President Donald Trump said the ruling was great news for America.
He also urged incoming Democratic Senate minority leader Chuck Schumer and Democratic Speaker of the House Nancy Pelosi to “pass a STRONG law that provides GREAT healthcare”.
The case is now likely to go to the US Supreme Court.