How big is the constitutional challenge to the Obama health care law, which the Supreme Court will hear on March 26-28?

For starters, it’s big enough for the justices to schedule six hours of arguments — more time than given to any case since 1966. After all, the Affordable Care Act is arguably the most consequential domestic legislation since the creation of Medicare in 1965.

It’s also big enough to attract more briefs than any other case in history. At least 170, including more than 120 “friend-of-the-court” or amicus briefs, have been filed, many of which are joined by 10, 20 or more groups of every imaginable description.

And, finally, it’s big enough to cause the justices to postpone until October half of the 12 cases that they would ordinarily hear in April in order to clear time to get started on the health care opinions that they are expected to issue by the late June, or possibly, early July.

What’s it all about?

The immediate issues, in the order the court will hear them, begin with the question of whether the so-called “individual mandate” — which requires that almost all Americans without coverage buy individual health insurance policies or pay fines — is ripe for adjudication now. Or must the case be deferred until 2015 because of the 1867 Anti-Injunction Act, which bars federal courts from ruling on the constitutionality of tax laws before payments are due?

After that come the arguments about what many consider the central issue: whether the mandate, which is unprecedented, should be voided because it represents an unconstitutional exercise of Congress’ powers to regulate commerce and to levy taxes.