The first-half numbers are in, and it's looking great for Toyota (NYSE: TM): The resurgent Japanese giant was the world's top-selling automaker through the first six months of 2012.

Longtime king General Motors (NYSE: GM) regained the full-year sales crown from Toyota last year, of course, thanks to the March 2011 tsunami that crippled Toyota production lines, to some dubious counting in China, and -- to be fair ­­-- to some much-improved cars and trucks from the General.

But at least for now, Toyota's on track to take it back in 2012. Can GM mount a challenge before year's end?

Toyota leads a three-horse race -- for the moment
The GM-Toyota global sales rivalry gets a lot of press, but we should be clear up front that this is actually a three-horse race. Volkswagen (OTC: VLKAY), which is the largest carmaker in Europe and which sells almost as many vehicles in China as GM does, has set a goal of taking the crown by 2018 -- and it's already closing on the longtime leaders.

But Toyota's the leader at least at the moment. The Japanese giant's global sales rose 34% in the first six months of 2012 to 4.97 million, about 300,000 ahead of GM and 520,000 up on VW. That big year-over-year surge is the result of Toyota's recovery from last year's natural disasters, disasters that damaged factories belonging to key suppliers and caused production slowdowns and disruptions in Toyota factories around the world.

But there are other factors at work, factors that could continue to play to Toyota's advantage as the year goes on.

Why Toyota could retain the advantage for a while
Toyota doesn't have much of a presence in Europe, but the European economic crisis has hit both GM and VW hard. Sales at GM's important German subsidiary Opel were down about 8% through the first half of the year. As bad as that sounds, it was slightly better than the overall market -- and better than rival Ford (NYSE: F), which posted a 10% decline and is contemplating a major overhaul. VW, which sells one out of every four cars sold in Europe (but sells more of them in relatively strong countries like Germany), saw less of a decline than either of the Detroit giants. But it's still vulnerable to economic disruptions, which could worsen as the year goes on.

Toyota, on the other hand, derives much of its strength from the U.S. market, which has been surprisingly strong, and from its home market of Japan, where it is the undisputed leader. Those are good places to be strong right now: The overall U.S. auto market was up 14.6% through the first half of the year -- and Toyota's sales, after a rough couple of years, have been especially strong here. VW, too, has pushed hard to expand its U.S. presence -- a deliberate strategy to offset weakness in Europe -- and has reaped big rewards, with sales up 35.4% here through the first six months of 2012.

Meanwhile, while GM still leads the U.S. market, it has struggled a bit at home as of late. The General's U.S. market share has dropped substantially over the past year, thanks to a still-dated product line and lingering resentment over GM's taxpayer-funded bailout in an election year. GM has a slew of new products on the way, and that -- along with the end of election season --should help the General's considerably, but probably not until 2013.

But what about China?
The Chinese auto market is probably less of a factor in the global sales race, if only because all three automakers are heavily exposed to the world's largest auto market. GM and VW are the 800- and 795-pound gorillas, of course, and thus especially vulnerable to swings in the Chinese auto market -- in either direction. But Toyota also has a sizable presence in the Middle Kingdom, where -- surprise -- it has turned out that Chinese consumers like Toyota's reputation for reliability and fuel efficiency just as American consumers do. That makes it less likely to be a significant factor in this horse race.

The upshot: Global economic and business factors would seem to favor Toyota, for the moment.

The upshot: Does it matter?
GM CEO Dan Akerson has said that he's more concerned about profits than sales crowns, and while that's certainly the right attitude for him to take, this stuff does matter on some level -- if only to the companies themselves. Most consumers -- in the U.S., or China, or wherever -- trying to decide between a Camry and a Malibu are unlikely to make the decision based on the global sales standings, but brand reputation matters, and being No. 1 probably conveys some subtle advantage.

So yes, it probably matters, at least a little bit. And how will this race end? We'll have to wait and see.

GM's stock is currently hovering near its post-bankruptcy low. But it could have significant upside in coming months, as new products hit showrooms and improvements continue around the world. However, investors need to stay attuned to fluctuating demand and the ability of automakers, like GM and Ford, to respond in unison. For starters, one of our top equity analysts has compiled a premium research report with in-depth analysis on Ford's competitive edge. To find out what could propel Ford down the road, get instant access to this premium report now.