Thomas Friedman REALLY seems to have had some sort of major epiphany about energy. He says green is the color of the new year.

I know that you should never generalize about global warming from your own weather, but as a longtime resident of Washington, D.C., it’s hard not to, considering that it’s been so balmy this winter season I’m half expecting the cherry blossoms to come out for Christmas. In fact, my wife was rummaging through her closet the other day and emerged to tell me she needed a whole new wardrobe — “a global warming wardrobe,” clothes that are summer weight but winter colors.

For this, and other reasons, had I been editing Time magazine I would not have opted for the “you” in YouTube as Person of the Year — although that was very clever. No, I’d have run an all-green Time cover under the headline, “Color of the Year.” Because I think that the most important thing to happen this past year was that living and thinking “green” — that is, mobilizing for the environmental/energy challenge we now face — hit Main Street.

For so many years the term “green” could never scale. It was trapped in a corner by its opponents, who defined it as “liberal,” “tree-hugging,” “girly-man,” “unpatriotic,” “vaguely French.”

No more. We reached a tipping point this year — where living, acting, designing, investing and manufacturing green came to be understood by a critical mass of citizens, entrepreneurs and officials as the most patriotic, capitalistic, geopolitical, healthy and competitive thing they could do. Hence my own motto: “Green is the new red, white and blue.”

How did we get here? It was a combination of factors: Katrina, Al Gore’s terrific movie, the growing awareness that our gas guzzlers are financing the terrorists, preachers and rogue regimes we’re fighting, the real profits that major companies like G.E. and DuPont are making by going green, and the fact that even the Pentagon has given birth to “Green Hawks,” who are obsessed with powering our army with less energy.

The most telling sign was the last election, when “being green became pragmatic,” said the Democratic pollster Stan Greenberg. “No one thought that running an ad on alternative energy was something for an elite target audience anymore. The only debate we had was whether it was one of the three things a candidate should talk about or the only thing.”

And now, Wal-Mart. Wal-Mart has earned its black eyes for labor practices. But the world’s biggest retailer lately has gotten the green bug — in part to improve its image, but also because it has found that being more energy efficient is highly profitable for itself and its customers.

Wal-Mart has opened two green stores where it is experimenting with alternative building materials, lighting, power systems and designs, the best of which it plans to spread to all its outlets. I just visited the one in McKinney, Tex. From the big wind turbine in the parking lot and solar panels on key walls, which provide 15 percent of the store’s electricity, to the cooking oil from fried chicken that is recycled in its bio-boiler and heats the store in winter, to the shift to L.E.D lights in all exterior signs and grocery and freezer cases — which last longer and sharply reduce heat and therefore the air-conditioning bill — you know you’re not in your parents’ Wal-Mart.

Other big companies are now sending teams to inspect the green Wal-Marts, and customers are asking the manager how they can adopt these innovations at home.

“When I started having people stop me in the aisles and say, ‘How do I do that?’ or ‘Can I do that?’ that’s when we really started realizing that this isn’t just a small thing, this can be really large and can be very rewarding to the planet,” said the store’s manager, Brent Allen.

Hey, the more energy-saving bulbs Wal-Mart sells, the more innovation it triggers, the more prices go down. That’s how you get scale. And scale is everything if you want to change the world, but to achieve scale you have to make sure that green energy sources — biofuels, clean coal, and solar, wind and nuclear power — can be delivered as cheaply as oil, gas and dirty coal. That will require a gasoline or carbon tax to keep the price of fossil fuels up so investors in green-tech will not get undercut while they drive innovation forward and prices down. The U.S. Congress has to stop running from this fact.

Because while our embrace of green has finally reached a tipping point, the tipping point on climate change and species loss is also fast approaching, if it’s not already here. There’s no time to lose. “People see an endangered species every day now when they look in the mirror,” said the environmentalist Rob Watson. “It is not about the whales anymore.”

Paul Krugman has some thoughts about cleaning up the deficit mess. But apparently not just now … … spending is good, too.

Now that the Democrats have regained some power, they have to decide what to do. One of the biggest questions is whether the party should return to Rubinomics — the doctrine, associated with former Treasury Secretary Robert Rubin, that placed a very high priority on reducing the budget deficit.

The answer, I believe, is no. Mr. Rubin was one of the ablest Treasury secretaries in American history. But it’s now clear that while Rubinomics made sense in terms of pure economics, it failed to take account of the ugly realities of contemporary American politics.

And the lesson of the last six years is that the Democrats shouldn’t spend political capital trying to bring the deficit down. They should refrain from actions that make the deficit worse. But given a choice between cutting the deficit and spending more on good things like health care reform, they should choose the spending.

In a saner political environment, the economic logic behind Rubinomics would have been compelling. Basic fiscal principles tell us that the government should run budget deficits only when it faces unusually high expenses, mainly during wartime. In other periods it should try to run a surplus, paying down its debt.

Since the 1990s were an era of peace, prosperity and favorable demographics (the baby boomers were still in the work force, not collecting Social Security and Medicare), it should have been a good time to put the federal budget in the black. And under Mr. Rubin, the huge deficits of the Reagan-Bush years were transformed into an impressive surplus.

But the realities of American politics ensured that it was all for naught. The second President Bush quickly squandered the surplus on tax cuts that heavily favored the wealthy, then plunged the budget deep into deficit by cutting taxes on dividends and capital gains even as he took the country into a disastrous war. And you can even argue that Mr. Rubin’s surplus was a bad thing, because it greased the rails for Mr. Bush’s irresponsibility.

As Brad DeLong, a Berkeley economist who served in the Clinton administration, recently wrote on his influential blog: “Rubin and us spearcarriers moved heaven and earth to restore fiscal balance to the American government in order to raise the rate of economic growth. But what we turned out to have done, in the end, was to enable George W. Bush’s right-wing class war: his push for greater after-tax income inequality.”

My only quibble with Mr. DeLong’s characterization is that this wasn’t just one man’s class war: the whole conservative movement shared Mr. Bush’s squanderlust, his urge to run off with the money so carefully saved under Mr. Rubin’s leadership.

With the benefit of hindsight, it’s clear that conservatives who claimed to care about deficits when Democrats were in power never meant it. Let’s not forget how Alan Greenspan, who posed as the high priest of fiscal rectitude as long as Bill Clinton was in the White House, became an apologist for tax cuts — even in the face of budget deficits — once a Republican took up residence.

Now the Democrats are back in control of Congress. They’ve pledged not to be as irresponsible as their predecessors: Nancy Pelosi, the incoming House speaker, has promised to restore the “pay-as-you-go” rule that the Republicans tossed aside in the Bush years. This rule would basically prevent Congress from passing budgets that increase the deficit.

I’m for pay-as-you-go. The question, however, is whether to go further. Suppose the Democrats can free up some money by fixing the Medicare drug program, by ending the Iraq war and/or clamping down on war profiteering, or by rolling back some of the Bush tax cuts. Should they use the reclaimed revenue to reduce the deficit, or spend it on other things?

The answer, I now think, is to spend the money — while taking great care to ensure that it is spent well, not squandered — and let the deficit be. By spending money well, Democrats can both improve Americans’ lives and, more broadly, offer a demonstration of the benefits of good government. Deficit reduction, on the other hand, might just end up playing into the hands of the next irresponsible president.

In the long run, something will have to be done about the deficit. But given the state of our politics, now is not the time.