I agree with you that China and Dubai and Singapore are all interested in controlling port terminals.
I think you need a crystal ball when you draw a line between them wanting to conduct business and them wanting to help blow up a port or use a port to help terrorists. Just think, if Dubai or China screwed up at just one port, they would have to kiss their whole shipping/port business goodbye.
We live in a global economy and that is nothing but good for the United States. The United States profits from participating in the global economy. We will only remain a super-power as long as we participate in that global economy. In the late 70's and 80's Americans opted out of the port terminal managing business because it wasn't profitable at the time. That is not China's fault, or Singapore's fault or Dubai's fault. It's certainly not Bush's fault. I'm of a mind that it's no one's fault, but the Americans that were originally in the port business who sold out.
So now we have a few companies that are qualified to do this business and can afford to win the bids for the business. They all have exemplary records in the business. There is no reason to stop any of them from doing business in the United States.
So...where do we differ?