We don't borrow money from China.
We offer bonds with very low interest rates on an open market... one of the largest buyers of these bonds is the PRC.
Owning a bond, or several billion of them, does not entitle you to anything but the agreed upon terms set when you purchased the bond.
If you buy stock in a company and those shares don't come with voting rights, you can conceivably own a majority of the company's wealth and still have ZERO power over the company. For example, Google has shares that are given 10 votes per share, owned mostly by the founders of the company. If any single entity owned every share other than those 10 vote shares, they still are not entitled to control the company.
Finally, national debt isn't a debt in a traditional sense. Bonds are issued against wealth that is not liquid in order to use that wealth to promote further growth. People pull out equity on their homes to make improvements all of the time... their net worth can actually increase even though they actually owe the bank more money. The fact that the US is considered to have so much value that we can issue bonds to the tune of Trillions at 0 interest goes to show that our nation is doing VERY well financially, we haven't even begun to over extend ourselves. True, at some point we will have to repay the bonds, but the hope is that when we do, our nation will be worth more than before due to the investments made with the cash we received from their sale. To repay, we just sell more bonds.
Any 2nd year business major can tell you that a corporation that doesn't leverage its assets in order to gain capital for further investments is a corporation that is poorly run. Corporations cannot operate on revenue alone, they need to sell stock or take out loans against the value of the company in order to capitalize their growth. Thats what the US does, and should be doing. Part of me would love to see just how much cash we could rake in if we tried... can you imagine how it would effect the value of our nation if we instantly doubled our investment in education, research, and infrastructure. Those are investments that we should be making and the way to do it is to leverage our worth.