(Source: The New York Times)

Indulge me while I tell you a story — a near-future version of Charles Dickens’s “A Christmas Carol.” It begins with sad news: young Timothy Cratchit, a k a Tiny Tim, is sick. And his treatment will cost far more than his parents can pay out of pocket.

Fortunately, our story is set in 2014, and the Cratchits have health insurance. Not from their employer: Ebenezer Scrooge doesn’t do employee benefits. And just a few years earlier they wouldn’t have been able to buy insurance on their own because Tiny Tim has a pre-existing condition, and, anyway, the premiums would have been out of their reach.

But reform legislation enacted in 2010 banned insurance discrimination on the basis of medical history and also created a system of subsidies to help families pay for coverage. Even so, insurance doesn’t come cheap — but the Cratchits do have it, and they’re grateful. God bless us, everyone.

O.K., that was fiction, but there will be millions of real stories like that in the years to come. Imperfect as it is, the legislation that passed the Senate on Thursday and will probably, in a slightly modified version, soon become law will make America a much better country.

So why are so many people complaining? There are three main groups of critics.

First, there’s the crazy right, the tea party and death panel people — a lunatic fringe that is no longer a fringe but has moved into the heart of the Republican Party. In the past, there was a general understanding, a sort of implicit clause in the rules of American politics, that major parties would at least pretend to distance themselves from irrational extremists. But those rules are no longer operative. No, Virginia, at this point there is no sanity clause.

A second strand of opposition comes from what I think of as the Bah Humbug caucus: fiscal scolds who routinely issue sententious warnings about rising debt. By rights, this caucus should find much to like in the Senate health bill, which the Congressional Budget Office says would reduce the deficit, and which — in the judgment of leading health economists — does far more to control costs than anyone has attempted in the past.

But, with few exceptions, the fiscal scolds have had nothing good to say about the bill. And in the process they have revealed that their alleged concern about deficits is, well, humbug. As Slate’s Daniel Gross says, what really motivates them is “the haunting fear that someone, somewhere, is receiving social insurance.”

Finally, there has been opposition from some progressives who are unhappy with the bill’s limitations. Some would settle for nothing less than a full, Medicare-type, single-payer system. Others had their hearts set on the creation of a public option to compete with private insurers. And there are complaints that the subsidies are inadequate, that many families will still have trouble paying for medical care.

Unlike the tea partiers and the humbuggers, disappointed progressives have valid complaints. But those complaints don’t add up to a reason to reject the bill. Yes, it’s a hackneyed phrase, but politics is the art of the possible.

The truth is that there isn’t a Congressional majority in favor of anything like single-payer. There is a narrow majority in favor of a plan with a moderately strong public option. The House has passed such a plan. But given the way the Senate rules work, it takes 60 votes to do almost anything. And that fact, combined with total Republican opposition, has placed sharp limits on what can be enacted.

If progressives want more, they’ll have to make changing those Senate rules a priority. They’ll also have to work long term on electing a more progressive Congress. But, meanwhile, the bill the Senate has just passed, with a few tweaks — I’d especially like to move the start date up from 2014, if that’s at all possible — is more or less what the Democratic leadership can get.

And for all its flaws and limitations, it’s a great achievement. It will provide real, concrete help to tens of millions of Americans and greater security to everyone. And it establishes the principle — even if it falls somewhat short in practice — that all Americans are entitled to essential health care.

Many people deserve credit for this moment. What really made it possible was the remarkable emergence of universal health care as a core principle during the Democratic primaries of 2007-2008 — an emergence that, in turn, owed a lot to progressive activism. (For what it’s worth, the reform that’s being passed is closer to Hillary Clinton’s plan than to President Obama’s). This made health reform a must-win for the next president. And it’s actually happening.

So progressives shouldn’t stop complaining, but they should congratulate themselves on what is, in the end, a big win for them — and for America.