WASHINGTON (MarketWatch) — After months of speeches, rallies and campaign ads, President Barack Obama and Mitt Romney will finally face each other Wednesday to debate who is the better leader for the next four years.

If Wednesday night’s presidential debate goes according to script, the two candidates will avoid many of the nation’s most pressing economic challenges, preferring to fight the political wars on familiar, focus-group-tested turf — bickering over tax rates, energy policy, the welfare state and defense spending.

Debates: Little things matter

Those are important issues, to be sure, but no one really thinks any of them are the key to America’s future. Would we be a much different country if we lowered the top tax rate a little, or raised it a little? Would drilling for oil and gas everywhere really transform our economy? Would cutting $60 billion in Pentagon spending really threaten our position as the world’s only military superpower?

The things the candidates are talking about most would have very little direct or immediate impact on most Americans.

What is America’s most pressing problem? In the short run, it’s finding productive and rewarding jobs for some 20 million people who are unemployed, underemployed or completely discouraged. Both candidates have jobs plans, but none of their ideas measures up to the need.

Finding good jobs is also our biggest long-run challenge.

In case you haven’t noticed, this is a problem for the whole world, not just the United States. The global economic-growth model that relies on First World consumption and Third World production is failing, not only in the United States but in Europe and in Asia as well. Americans are consuming as fast as they can, but it’s not enough to create full employment — not here and not in China, either.

Barack Obama and Mitt Romney

The U.S. economy is creating just about as many jobs as it can, given the weak fundamentals. Neither Obama nor Romney can explain how their proposed policies would create the conditions necessary to accelerate job creation.

Let’s break it down, looking at each of the components of growth in turn: Consumer spending can’t do more; we’re strapped. Businesses won’t invest more without the prospect of more customers. Export markets are shrinking. In this era of fiscal McCarthyism, government isn’t allowed to fill in the gap; indeed, we know that the fiscal drag will get worse next year, even if the cliff is avoided.

The only strengthening source of growth is home building, but that won’t carry the economy the way it did in 2004.

The two candidates talk a lot about the deficit, but they are focused on the wrong one. The federal government’s debt does need to be addressed eventually, but it’s the deficit with the rest of the world that represents the bigger danger to our way of life. I’m talking about the trade deficit, or more precisely, the current account deficit, which includes capital flows as well as trade in goods and services.

“ We needn’t accept a race to the bottom in terms of wages or corporate governance or social responsibility. ”

In the past 30 years, the United States has run a current account surplus in only one year: 1991. Under Republicans and Democrats alike, the current account deficit has averaged 2.9% of our gross domestic product every year. It’s amounted to $8.7 trillion since 1982. Over the past 10 years, it’s averaged $583 billion a year.

The current account deficit is the amount we borrow from the rest of the rest of the world to finance our consumption and investment. It’s how much we spend beyond our means. It’s how much of the world’s savings is funneled into the United States.

The current account deficit is the symptom of how uncompetitive we’ve become.

It’s the reason our interest rates are low, our consumer goods are cheap and our jobs are scarce. It’s part of the reason our government budget is perennially in deficit, and it’s a big reason inequality is growing in this country. A large current account deficit is the main thing we have in common with Greece.

Have you heard either Obama or Romney talk about the current account deficit? Aside from the usual bromides about how free-trade agreements will save us, or the empty threats to “get tough on China,” the topic has been off-limits.

Yet reducing our deficit with the world would create jobs, especially manufacturing jobs. In this environment, it may be the only way to create a significant number.

Why won’t Obama or Romney make it an issue? Perhaps because the large companies and wealthy individuals who control our political system are happy with the large and growing deficit: It keeps wages down and profits up. Or perhaps it’s because doing something about it would be painful.

Bringing the current account deficit down would require a weaker dollar, which would make imports relatively more expensive and U.S.-made goods relatively cheaper. Until production shifted back to America, consumers would feel it every time they shopped.

Addressing the deficit would require taking a skeptical view of the benefits of so-called free-trade agreements. It would require “getting tough” with our trading partners to make sure they aren’t subsidizing their exports to us. It would require investments in our own human and physical capital to make sure we are competitive in the global economy.

Globalization isn’t a force of nature beyond our control. The United States has considerable clout in negotiating the terms of trade. We needn’t accept a race to the bottom in terms of wages or corporate governance or social responsibility. We can help lift the rest of the world to our standards.

Remember, the Chinese — and the rest of the developing world — need us a lot more than we need them. And the president who’s sworn in on Jan. 20 needs to act.