US President Donald Trump, a vocal critic of the legislation - a legacy of the administration of US President Barack Obama that provided health coverage for low-income American citizens and permanent residents - praised the court ruling and said on Wednesday that the decision would not change the current US healthcare system.
" The individual mandate, by far the worst element of Obamacare, is unconstitutional. This decision will not alter the current healthcare system. My administration continues to work to provide access to high-quality healthcare at a price you can afford, while strongly protecting those with pre-existing conditions", Trump said.
Wednesday's court ruling, however, did not say whether the rest of the law can remain in place or be struck down, instead of sending the case back to a district court judge for further analysis.
California Attorney General Xavier Becerra - who heads a coalition of 20 Democratic-led states defending the law - said the ruling means Trump "got the gift he wanted - uncertainty in the healthcare system and a pathway to repeal", according to Reuters. California will appeal the decision to the Supreme Court, a spokeswoman for the state attorney general said, cited by Reuters.
Despite helping American citizens, Obamacare has reportedly prompted several US medical giants to leave the insurance market due to financial losses - a sticking point of the ongoing legal dispute between the GOP and the Dems in the landmark Obama-era legislation.
Obamacare relies on government-run exchanges in which insurance companies sell policies to individuals and families that lack employer-provided health insurance plans. The United States, unlike much of the developed world, does not make free high-quality healthcare available to citizens.