With the uneven playing field of wages, working conditions, and government subsidies, China has been able to "steal" productive lobs from U.S. citizens. Along with their import restrictions and tariffs of American made goods, they are unfairly becoming the worlds dominant producer of goods. The more they grow, the more American jobs will be lost.
I believe that a booming China does mean trouble for America because the United States is already deeply in debt to China thanks to the massive costs of two wars in the Middle East. As China continues to grow and expand, the Chinese economy could eventually replace the U.S. economy as the primary economic nation in the world. Paying down the U.S. debt is vital to competing with China.
America is a wealthy country that has close economic ties. Its success is not that bad for us, however in the long run they could easily overtake us as the worlds leading economy. They are still a long way off and have problems that need to be solved, but their success is a good thing. All countries should be successful..
China's growth has to level off sometime. Eventually, Chinese workers will make just as much as American laborers on minimum wage. Chinese currency will have to become traded on the free market sometime in the future. China will have no choice but to turn into a free market economy to catch up to the rest of the world. China's growth has to stop sometime by the very nature of supply and demand economics.