Washington (CNN) — The Supreme Court in coming days will issue perhaps as many as four separate opinions on the constitutionality of the health care law .

The Patient Protection and Affordable Care Act (PPACA or ACA) was signed into law March 23, 2010, passed by a Democratic congressional majority and championed by President Barack Obama. It has about 2,700 pages and contains 450 some provisions.

Here are the four issues the high court tackled separately during oral arguments in late March. Those issues are expected to play key roles in the judges’ final decisions.

The gateway issue: Anti-Injunction Act

Would those challenging the law be barred from making any legal or constitutional claims until the key provision — the individual mandate — goes into effect in 2014? The obscure Anti-Injunction Act, dating back 145 years, prevents asking for a refund on a tax until that tax has been collected and paid. Judges in two federal appeals courts have made that “threshold” argument, which would effectively stop the current legal fight in its tracks. Continue reading Health care’s big four issues: What the justices are tackling! →