Third, you'll find that China has unique product standards that make life particularly hard for you. Let's say you're a bulldozer manufacturer. International rules say the length of the drivers' step for the driver has to be between 28 and 30 inches. In China? The standard is between 30 and 36 inches. (Why? Because!) That means you have to modify the production line, making the bulldozer more expensive.

That's just the tip of the iceberg when it comes to trade barriers. Punishing taxes and tariffs can make American products so expensive that nobody in China wants to buy them. But the biggest problem is government procurement rules, says Frank Vargo, vice president at the National Association of Manufacturers. Let's explain that phrase quickly: The Chinese government is a $100 billion market, but it insists on buying only "domestic" goods, which shuts out major U.S. companies from that $100 billion pie. For Chinese companies, that means a cozy environment to practice technologies until they're world class. For U.S. companies, especially in the high tech industry, it means a lot of closed doors in China and stiff competition with heavily subsidized Chinese companies abroad. (Trade barriers are a problem with many countries, but in China they cast the longest shadow.)

Intellectual Property Theft

The United States runs a trade surplus in services like licensing technology. But if China steals what we're selling, then ... well, we can't sell it. Technology companies say they notice the Chinese downloading software updates for software programs they've never bought. David Leonhardt points out that China has become the world's second-largest market for computer hardware sales, but only the eighth-largest for software sales. That's the IP theft gap in a stat. Sometimes, the Chinese steal from right under our noses. When a crane manufacturer named Manitowoc designed restaurant equipment for local Chinese restaurants, Chinese competitors stole the designs. Who wants to do business somewhere their ideas won't be protected?

Currency Wars

The significance of our exchange rate can be exaggerated [read more on that here], but it's still key to our competitiveness. In a sentence: When the dollar is overvalued, our exports become too expensive, and overseas clients buy less stuff. Here's the story in two graphs:

When the dollar rises against a broad basket of currencies, our export growth rate plummets. It's happened twice in the last 40 years, in the mid-1980s and in the mid-2000s. If the dollar starts to climb that mountain again, expect our export growth to slide into another valley.

CHALLENGES AT HOME

Taxes

The most important constraint to U.S. trade might be the way we tax companies. We have what will soon be the highest corporate tax rate in the developed world now that Japan, the current leader, is slowly bringing down its rate. One reason why multinational companies prefer to set up subsidiaries abroad is to escape U.S. taxes. Even Google, despite its unofficial pledge to not "be evil," famously funnels its revenue abroad to avoid being hit by our 35 percent tax rate on stateside income. The United States can't compete with the labor rates in smaller economies, but a lower tax rate could bring U.S. business back to the U.S.