Do UNIONS cost American jobs?

Unions are good to workers, as they allow them to negotiate a higher wage. It is sometimes true that unions can be too powerful and they can negotiate a wage that is unreasonably high. However, the union is not entirely at fault, because sometimes the workers themselves may go on wildcat strikes if they think the union did not negotiate a good enough contract. Certainly there is greed among the workers, but then if we look at CEO salaries, they are even more unreasonable. Therefore greed is at work on both sides. Sometimes jobs are exported not because the companies cannot afford the union wages, but because the CEO and other executives want an even bigger paycheck. Therefore we should not leap to the conclusion that it is the union's fault if a company moves the factory. It happens even in China. Sometimes a factory is moved from China to some place like Vietnam or Malaysia, because the wages are even cheaper, even though there is no union in the Chinese shops. That is why the Chinese are resisting the American push to increase the value of their currency. It makes labor costs higher in China, and therefore companies may move their factories elsewhere.