Obamacare is no mere paper law. No indeed. For the GOP’s ideological Captain Ahabs, it has become a public-policy white whale, a leviathan that must be harpooned at any cost. So it is that the Tea Party types are now demanding that Republican office-holders resort to shut-down-the-government brinksmanship to slay the cetaceous statute.

For those with long memories, the spectacle can be amusing. A key piece of the Affordable Care Act is the requirement that those who don’t have health care coverage purchase a policy. That was once a credentialed conservative idea, an exemplar of personal responsibility popularized by the Heritage Foundation. From there, it became a Republican congressional alternative to Hillarycare and then the centerpiece of Romneycare, whose elaborate signing ceremony included a speaker from the conservative think tank.

But then Obama adopted the individual mandate as part of his plan — whereupon conservatives declared it an intolerable intrusion on liberty. Thus we have the diverting spectacle of Jim DeMint, the former South Carolina senator who now heads the very same Heritage Foundation that popularized the individual mandate, warning that its implementation signals “the point of no return” for the American health care system.

If Heritage seems more than a little cockeyed, it’s hardly alone. Remember back when raising taxes on upper earners was going to derail the slow-moving recovery? That didn’t happen, but now the air is full of equally dire warnings that Obamacare’s (delayed) employer mandate will be a crippling blow to small businesses.

Why, “Seventy-five percent of small businesses now say they are going to be forced to either fire workers or cut their hours,” warns Florida Sen. Marco Rubio. “Pants on Fire” (as in liar, liar) judged PolitiFact.com, the Pulitzer Prize-winning truth squad, which scrutinized the study at the core of Rubio’s claim and found that actually, only 5 to 9 percent of the companies surveyed said they would either replace full-time workers with part-timers or cut hours.

Another favorite Republican rhetorical trick is to claim that 8.2 million Americans are unable to find full-time work partly due to Obamacare. Hmmm. As FactCheck.org, another probity prober, notes, the number of people working part-time for want of a full-time job skyrocketed from about 4.5 million back in mid-2007 to more than 9 million in 2008, before Barack Obama was even in office. It has been on a slow, stutter-step decline for the last several years. That reality makes it comical to blame the Affordable Care Act for the 8.2 million part-timers hoping for full-time work.

Then there’s Tea Partying Texas Sen. Ted Cruz, who recently declared that “there is no legislation in effect that is damaging the economy more or damaging jobs more than Obamacare.”

Actually, as PolitiFact notes, mainstream economists think the federal spending cuts due to the sequestration have been much more of a drag on job growth.

Now, no one can say with certainty that the Affordable Care Act will work as planned. It will doubtless have some negative effects and need some adjustments. Every big law does. But from expanding coverage to millions to prohibiting lifetime limits on plan benefits to banning exclusions based on preexisting conditions, the many positive effects should outweigh the negative ones.

Several points are worth keeping in mind as more information comes in.

First, one big reason some health-plan premiums will increase is that, under Obamacare, health plans will offer more comprehensive coverage. Second, the law will provide extensive subsidies to help those of moderate and middle means buy insurance.

The most interesting recent overall prognosis I’ve heard comes from John McDonough, who worked on the law as an aide to Ted Kennedy and now follows it closely as a professor at the Harvard School of Public Health. States whose leaders dedicate themselves to making the law work will see good results, he predicts. States whose leaders try to undermine it may not.

If so, that will lead to the compare-and-contrast phase of the Obamacare debate, a period that will be informed by actual facts and a sense of the achievable real-life results.

The betting here is that phase won’t prove kind to the crew of the political Pequod.

Scott Lehigh is a columnist for The Boston Globe.