I’m no expert on American politics, but I do know something about holes. And watching the way the Republican Party is reacting to the passage of health care, it seems to me the G.O.P. is violating the first rule of holes: “When you’re in one, stop digging.”

Yes, I know, the polls show that the G.O.P. is not being hurt by its “just-say-no” strategy. But there is no groundswell moving its way either. Republicans will have to come up with more than “just-say-no-to-everything-except-lower-taxes-and-more-drilling” to field a credible 2012 presidential candidate. Here’s why:

If you step back far enough, you could argue that George W. Bush brought the Reagan Revolution — with its emphasis on tax cuts, deregulation and government-as-the-problem-not-the-solution — to its logical conclusion and then some. But with a soaring deficit and a banking crisis caused by an excess of deregulation, Reaganism has met its limit. Meanwhile, President Obama’s passage of health care reform has brought the New Deal-Franklin Roosevelt Revolution to its logical conclusion. There will be no more major entitlements for Americans. The bond market will make sure of that.

In other words, both major parties have now completed their primary 20th- century missions, first laid down by their iconic standard-bearers. The real question is which party is going to build America’s bridge to the 21st century — one that will strengthen our ability to compete in the global economy, while practicing much more fiscal discipline.

Obama is at least trying to push an agenda for pursuing the American dream in these new circumstances. I don’t agree with every policy — I’d like to see a lot more emphasis on innovation and small business start-ups — but he’s clearly trying. I do not get that impression from the Republicans, and especially those being led around by the Tea Partiers.

Obama-ism posits that we are now in a hypercompetitive global economy, where the country that thrives will be the one that brings together the most educated, creative and diverse work force with the best infrastructure — bandwidth, ports, airports, high-speed rail and good governance. And we’re in a world with a warming climate that is growing from 6.8 billion people to 9.2 billion by 2050, so demand for clean energy is going to go through the roof. Therefore, E.T. — energy technology — is going to be the next great global industry.

So, government matters. It needs to be incentivizing businesses to build their next factory in this country — at a time when every other nation is throwing incentives their way; it needs to be recruiting highly skilled immigrants; it needs to be setting the highest national education standards and funding basic research; it needs to be laying down the right energy regulations that will stimulate more clean-tech companies.

And — something neither Democrats nor Republicans have stepped up to yet — we will need to pay for all this by simultaneously raising some taxes, cutting others and by taking away some services to pay for needed new investments in infrastructure and education. We can’t get away anymore with a G.O.P. that wants to cut taxes but never specifies which services it plans to give up, or a Democratic party that wants to add services by taxing only the rich.

“Health care was the final act of the New Deal,” argues Edward Goldberg, who teaches global business at Baruch College and is writing a book on globalization and U.S. politics. “The 21st-century will require a mix of cutting, investing and innovation and entrepreneurialism beyond anything we have dreamed of.” To simply say that government is not the answer, he adds, “when we are essentially fighting four wars — Iraq, Afghanistan, the Great Recession and the retooling of the American economy” — is ludicrous. Smart government needs to be the leader or silent partner in all of these projects.

One reason the G.O.P. has failed to spawn an agenda for the 21st century is that globalization has fragmented the party. Its Wall Street/multinational corporate wing understands we need immigration, free trade, clean-tech and government support for better infrastructure and the scientific research that is the wellspring of innovation. The Tea Party wing opposes virtually all those things. All that unites the two wings is their common desire for lower taxes — period.

Globalization has also weakened the Democrats’ blue-collar/union base, but the Democrats have absorbed a new constituency created by globalization — what Goldberg calls the “ ‘Newocracy’ — which combines the multinational corporate manager, the technology entrepreneur and engineer, and the aspirational members of the meritocracy.”

These “Newocrats” previously would have leaned Republican, but now many lean toward Obama. They don’t agree with everything he’s proposing, but they sense that he is working on that bridge to the 21st century, while today’s G.O.P./Tea Party is just not in the game. Today, we have no real opposition party with its own pathway to the 21st century. We just have opposition.