The UAW believes a breakthrough at the Volkswagen plant Tennessee or the Mercedes one in Alabama would be a historic turn for the union and manufacturing in the union-averse South, perhaps ultimately leading to a domino like action at other facilities.

However, it should be noted that Honda and Toyota factories in states such as Ohio and Indiana have also remained non-union even while operating in union-heavy rust belt areas.

The German workers are at least in part correct about the threat to their own jobs from non-union factories not only in the US but in India and other parts of the world too.

For example, in 2014 Mercedes will begin making a redesigned version of its C-Class sedan, a vehicle that up to now has been exported from Germany to the US. Would the extra costs associated with a unionized plant have altered that decision? That's hard to say, but when the plan to move C-Class production was first announced in 2009, 12,000 Daimler workers in Germany protested at the main production site of the car. Ultimately, Daimler reacted to the strife by agreeing to forgo involuntary layoffs in Germany until at least 2020. potentially creating something like the infamous "jobs banks" US companies endured for a couple of decades.

Some workers from the Vance plant have apparently gone to Germany to learn from IG Metall officials about German-style labor relations. But overall, US workers are in a different place - their wages are roughly equivalent to unionized workers here, and of course the new work to builld the C-Class vehicles is coming to the Vance plant, not being taken away.

But the labor costs in the US are generally much lower than costs in home markets in Germany and Japan. US auto workers received about $37per hour in wages and benefits on average last year, compared with about $59 in Germany.

Putting extra pressure on the UAW is the fact that the foreign transplants are in general growing faster than those of the "big three" US automakers that are heavily unionized, but whose numbers were decimated during the Great Recession, as that shock finally gave the US automakers the flexibility to shed capacity and close plants. Many auto parts makers did the same thing.

The number of union members in the auto sector has fallen from about 700,000 in 2000 to just under 400,000 today - about the same number as the recently rising count of non-union members. Thirty years ago, all cars made in the US were assembled by union workers at GM, Ford and Chrysler. Today, 38% of the vehicles made in the U.S. are built in non-union, foreign-owned factories.

Despite the collaborative and increasing global approach of the UAW with the German unions and others, and the pressure on German US factories, union success in the South is far from a given. Many of the workers at the Volkswagen and Mercedes plants here still do not want a union.

The Wall Street Journal quotes one Vance worker as saying he didn't trust IG Metall.

"They don't want us to get any more jobs in Alabama. They want to make sure jobs stay in Germany," he said.

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