Thomas Donlan of Barron’s places former U.S. House Speaker Nancy Pelosi’s infamous Obamacare quip (“we have to pass the bill so that you can find out what is in it”) in context.

It seems Pelosi meant that Americans would not fully understand how the bill would work until they could see it improving Americans’ health. By that grandmotherly standard, we still don’t know what’s in the bill. If free preventive care really improves the general level of health, it will take a few more years for the evidence to accumulate.

Right now, however, Pelosi’s remark is still more relevant to political science than to medical science. Intentionally or not, it was a fair statement of a principle in 21st century governance: What the Congress enacts is only the beginning of the legislative process.

Whatever the civics textbooks may say, a bill does not really become law until the rules and regulations implementing it are written by administrative agencies, formally proposed in the Federal Register, commented upon by interested groups and their lobbyists, revised, finally adopted, and — what is now the most important stage of lawmaking — litigated.

The process is so long and convoluted that the part played by Congress is diminished in importance. We really can’t know what a bill will mean until long after passage, when the courts tell us what the regulations mean.

The Affordable Care Act, which should be known as Pelosicare after its legislative shepherd but has been dubbed Obamacare, was signed on March 23, 2010. The rules have been under construction ever since. The legal battles over the rules and their meaning began almost as quickly, and won’t end for years.

It took until June 2012 for the fundamental case about the constitutionality of the individual mandate to be decided by the U.S. Supreme Court. That was the case in which Chief Justice John Roberts saved the law by transforming a penalty into a tax, and that judicial rewrite set the stage for many rewrites still to come. All of the rewrites are coming from the executive branch and the judicial branch, since the election of 2010 threw Congress into deadlock about Obamacare and almost everything else.