John McCain likes to say he is for economic growth. He offers a version of the narrative Republicans have pitched for years: Their party stands for lower taxes, less regulation and freer trade; Democrats stand for tax-and-spend, government intrusion and trade protectionism. But this juxtaposition now rings hollow. The real pro-growth candidate in this campaign looks to be Barack Obama.

McCain's problem is that his party's standard economic pitch has become less relevant. Lowering taxes was pro-growth in Ronald Reagan's time, when the top income tax rate was slashed from 70 percent to 50 percent, significantly changing incentives for work and risk-taking. But with the top rate at 35 percent today, a modest shift in either direction makes less difference.

The same goes for deregulation. Getting the nanny government out of trucking and airlines yielded huge benefits in the 1970s and 1980s. But the "price-and-entry" regulations that used to cosset such industries have long since gone, and remaining regulation is harder to demonize. We are left with government rules to protect the environment, check the safety of medicines and prevent systemic financial crises. These rules are generally helpful. There's nothing "pro-growth" about bashing them.

The same is approximately true for trade. When Bill Clinton ran for president in 1992, you couldn't be pro-growth if you were anti-trade because the creation of the North American Free Trade Agreement and the World Trade Organization hung in the balance. Today most trade barriers have been removed. Provided Obama can crawl back from his embarrassing talk of reopening NAFTA, the gap between his trade views and McCain's doesn't much matter.

The real litmus tests on growth lie elsewhere: education, basic science, skilled immigration, infrastructure and the grotesque tort system. Tax reform, not cuts, would help: The complexity of the tax code wastes millions of hours, and the crazy deductibility of mortgage interest encourages real estate bubbles. Regulatory reform, not deregulation, could help, too. Unless the United States consolidates its tangle of Wall Street overseers, creative financiers will flee and the country will lose its lead in a key 21st-century industry. But the old Republican playbook of tax cuts, deregulation and lower barriers to trade misses the real challenges.

On some of today's issues, it's hard to distinguish McCain from Obama. Neither has a bold plan for regulatory reform. Both have good instincts on immigration but have occasionally pandered to fence-builders. Both favor some measure of tort reform.

But on most of the issues where you can see a difference, Obama looks slightly better. The exception may be tax reform: McCain promises to simplify the code, though he glosses over the cost of his fixes. But Obama wants to double federal spending on basic scientific research. He wants to make broadband access universal. He has proposed an infrastructure bank to pump $60 billion into broken-down highways, ports and so on. If (and it's a big if) Congress could be prevented from turning this last proposal into a pork-fest, the growth payoff could be substantial.

The growth issue on which they have clashed is education. McCain is a firm supporter of President Bush's No Child Left Behind policy, which is based on a reasonable desire to hold bad schools accountable; Obama is mushier. But the research consensus on No Child Left Behind is actually quite mushy, too: Experts such as Cecilia Rouse of Princeton reckon that some accountability reforms can help (for example, Florida's seems good) but that No Child Left Behind may be too loosely designed to make much of a difference.

The one certainty about education is that holding schools accountable is only part of the solution. This is where Obama has the lead. He wants a big push on early-childhood education, which researchers believe can have an excellent payoff in terms of later achievement; he wants to address key gaps in teacher quality with higher pay; he wants a new tax credit to make college more affordable. A hundred years ago, the United States set the stage for the American century by investing more public money in education than other advanced economies. It needs to up its game again if it wants to retain its preeminence.

Of course, the campaign is not yet over. A few bold proposals from McCain could transform his economic credentials. But for now he is behind. Obama is the pro-growth candidate.

Sebastian Mallaby is a fellow for International Economics with the Council on Foreign Relations. He wrote this commentary for the Washington Post.