Maybe next year, but more likely the year after that, I believe Volkswagen will acquire Chrysler from private equity firm Cerberus.

The pieces fell into place during NAIAS. Over the past few months it has become clearer and clearer that Cerberus is in over its head. And private investors aren’t in for the long term regardless. So they’ll do their best to streamline the company in ways that an owner like Volkswagen could not get away with. Then they’ll unload it. Yes, and the sky is blue.

But why will Volkswagen be the buyer?

1. Volkswagen has decided that they want to surpass GM and Toyota to become the world’s largest automaker. At the auto show, they announced that they intend to grow U.S. sales from 300,000 to 800,000. That’s going to be very tough. Even tougher will be growing from roughly 6 million sales worldwide today to 10 million a decade from now–at a time when China and India will become major players. This level of ambition can lead companies to do irrational things–like buy Chrysler. While Renault-Nissan has also expressed interest in linking up with Chrysler, they simply don’t have the drive for growth that VW has.

2. To grow so much in the U.S., they’ll have to enter additional market segments. Chrysler is about to start supplying them with a version of its minivan. That will serve as a test of how well the two organizations can work together.

3. They’re probably also going to need a large pickup. And while looking at the 2009 Dodge Ram at the show I looked to my left, and found VW Chairman Ferdinand Piech and VW CEO Martin Winkerhorn standing at my elbow. Maybe their interest in the pickup was merely casual. After all, auto execs tour the show floor. But maybe not. If the minivan deal works out well, why not a pickup, too? In general, there is very little product overlap between the two companies. They’d be a great fit from this perspective.

5. VW wants U.S. production capacity, because the dollar is low and because they want to hedge against changes in exchange rates. Rumor is they’re going to build a new plant in the southeast. But they’re going to need more than one additional plant to realize their ambitions, and Chrysler has plenty of excess capacity.

I’m not saying this deal will happen tomorrow. Cerberus has work to do first. And the two organizations need to learn whether they can work together. A couple of years ought to do it. Look for a deal in 2010.