China has problems with the US's ability to encircle it on it's eastern end, it's political, economic and industrial centre, but to the East China is growing in influence. The new silk road and Pakistani industrial strip will allow China circumvent American Sanctions and blockades that would have destroyed China 5 years ago. While China still relies on marine trade to fuel it's export orientated industry in it is growing the capability to avoid this through the previously mentioned methods. Politically China has and is growing lots of influence in the middle east in places where America is less popular such as Iran. Through these countries it has access to many resources such as precious metals and oil. It is not in either parties interests to contest in a militaristic sphere or to completely break trade but over the next century China will have a greater ability to adapt and expand than the west as it still has large amounts of it's population which consumes few goods and generates little. Further more the new silk road and influence will allow them to militaristically act in the middle east to strengthen their own position and undermine the West's indirectly as they can use it as an excuse and an enabler to carry out military action which will not only gain it power through land, allies and resources it may obtain but it will also give it the experience it lacks. There are problems, China has a large but technologically inferior and less experienced military at the present and it relies heavily on money from exporting to the west and coal imported from Australia.
China has always been a competitor of the United States, but over the past few years, they have found a way to manufacture goods very cheaply, and sell them in the U.S. to impede on the profits and market share of U.S. companies. These are much lower quality goods, but many people continue to buy them because they are much less expensive than American alternatives. Many discount retailers, such as Walmart, are finally taking a stand and stating they will purchase American goods, and only buy from China if no American alternative is available. This will help American companies and American workers.
China is definitely a challenge for the United States. They have been for many years now. The U.S. is having problems right now in many areas while China seems to be prospering. Unless we turn things around we will be passed by China in the very near future because they do not seem to be slowing down.
If one ever doubted that China is becoming a competitive challenge to the U.S., they need only to go on a short shopping trip to one of their local stores such as Wal-Mart. There you will find very many products labeled "made in China" We have allowed this. We can only take the blame for our own actions. The campaign to buy only American made products if a good way to start turning this around. Unfortunately, there are not enough people joining in. The reason mostly is because the items made in China are far less expensive than the American made products.
China is advancing quickly in a lot of ways in terms of technology, their economy, etc. However, China is still way behind the U.S. In terms of human rights, and I don't believe that a country can really be considered a "challenge" to the U.S. When there is still a significant number of citizens who must follow the one-child policy, adhere to a restrictive government, and suffer from a crumbling infrastructure.