Short answers, pulled from the story.
A health insurance mandate is a legal requirement that individuals or employers obtain health insurance coverage. Individual mandates require people to purchase their own insurance, often with government subsidies for lower-income households and penalties for those who do not comply. Employer mandates require businesses above a certain size to provide coverage to their workers.
The Heritage Foundation proposed the individual mandate in 1989 as a conservative, free-market alternative to single-payer health care. Early Republican supporters included Charles Grassley, Mitt Romney, and John Chafee, who viewed it as consistent with the principle of individual responsibility.
The Tax Cuts and Jobs Act of 2017 set the Affordable Care Act's individual mandate penalty at zero dollars effective 2019. The act did not formally repeal the mandate, as full repeal was ruled to violate the reconciliation process, leaving the legal text in place but unenforceable through a financial penalty.
On the 28th of June 2012, the Supreme Court upheld the individual mandate 5-4 in National Federation of Independent Business v. Sebelius. Chief Justice John Roberts wrote the majority opinion, ruling that the mandate was not valid under the Commerce Clause but could be sustained as a tax under Congress's authority to lay and collect taxes.
Japan mandates that all residents carry health insurance through an employer or community insurer but imposes no financial penalty on those who do not comply. Around 10 percent of residents evade the requirement; those individuals simply do not receive an insurance card, which providers require for service.
After Massachusetts enacted its individual mandate in 2005-2006, more than 97 percent of state residents became insured, giving Massachusetts the lowest uninsured rate in the country. The year-to-year rate of premium growth also slowed compared to the rest of the United States between 2003 and 2008, though overall premiums remained above the national average.