(Fortune) -- Are we entering America's first globalization recession? I think we may well be, but before explaining why, I want to emphasize two points.

First, whether we're going into a recession at all is uncertain. Merrill Lynch's chief economist says we're already in one; Goldman Sachs's chief economist says we'll be in one by next quarter; Lehman Brothers' chief economist still doesn't expect one. Let's not worry about what to call it: The reality is that we're in a deep economic slowdown that will affect millions of people.

The second point is that I remain a huge fan of globalization. It will help more people than it hurts, in America and worldwide. But it will certainly produce new challenges, and today's economic situation looks like one of them.

The reasons we're in a major slowdown center on U.S. consumers, who drive the economy. Through the past six years they've been the most maniacal spending machines the world has ever seen. Stock market wobbles, rising interest rates, staggering personal debt, war, floods, hurricanes - nothing could slow them down. That was mainly because the value of their largest asset, housing, kept going up, and because they were confident about their jobs. As long as their home equity looked like a piggy bank and their paychecks looked solid, they just kept buying, and America's economic engine just kept turning.

Of course, home values have been declining for quite a while, and more recently the jobs picture has deteriorated markedly. What really slammed the door for many economists was the December employment report, which showed the unemployment rate jumping to 5% and a tiny number of jobs (18,000) created. With the home-equity ATM closed and paychecks looking iffy, it seems consumers have finally been forced to put the credit cards back in their wallets. Sure enough, after the holiday season a wave of retailers reported year-over-year sales drops for December. Department-store giant Macy's (M, Fortune 500), for instance, saw a 7.9% drop in same-store sales and noted an overall decline in consumer spending as a contributing factor.

Now what does any of that have to do with globalization? Quite a bit. Consider first the housing bubble. It was fueled by extraordinarily cheap money that lenders were virtually throwing at borrowers. As a result, the prices paid broke free of any connection to plausible values in relation to rents or total housing supply.

That superabundance of cheap money didn't come from Americans, since we haven't been saving for years. It came from the rest of the world, from what Fed chairman Ben Bernanke calls the "global saving glut." While we were spending, nearly everyone else on earth was saving at unprecedented rates, and those hundreds of billions of dollars made their way here. Not that anyone beat us with a stick and made us borrow the money or use it to pay ridiculous prices for homes; we can't blame anyone but ourselves for that. But the fact remains that without the global saving glut, we couldn't have had a housing bubble or the resulting housing collapse.

The jobs picture also has an important global dimension. For a majority of Americans, the most significant fact of globalization is the advent of a large-scale global labor market. Millions of people around the world can now compete for millions of U.S. jobs. Never mind that the number of jobs that actually get outsourced is relatively small. What matters is the mere presence of those lower-priced workers. They hold down the pay of high-priced Americans and constantly entice employers everywhere to create new jobs over there rather than here. Thus, the problem isn't so much jobs being sent abroad but jobs that never show up here at all.

To repeat, globalization remains a net plus for America and the world. But it means that we Americans must rethink our role in the world economy. We used to be the locomotive that pulls the train, and to a large extent we still are; Chinese factory owners will not be happy about a U.S. slowdown. But while we still influence the world economy, the new reality is that the world economy increasingly influences us.