Firstly, the deal is being widely misrepresented as DP World taking over or buying US ports. What they are acquiring is a terminal operator - a business that loads and unloads containers from ships - which operates within ports which are and will continue to be US owned, typically by local or state governments. These government authorities that own the ports will continue to have overall responsibility for port security under the regulatory eye of various agencies of the Department of Homeland Security.
As Ronald Reagan said, "trust but verify". But we'd rather take the easy way out. "Oh P&O are British so we don't have to worry about it." That kind of lazy thinking is absolutely asking for trouble.
It never ceases to amaze me how much energy gets devoted by our political class to issues that don't actually matter. Instead of worrying about who owns the company loading and unloading the containers they ought to be worrying about how they can make meaningful improvements in our ability to verify the who, what, when, where and why of the end-to-end supply chain. But that would take hard work, clear thought and real resources.
Update: The One Handed Economist said it to so much more elequently:
Dear Racist Half-Wits In Congress,
Please stop mucking about with this Dubai Port World deal. If you'd actually pay any attention to anything other than the fact that the United Arab Emirates is in the Middle East and has "Arab" in it's name you'd note that it's exactly the sort of moderate place we'd like other Middle Eastern nations to emulate. You'd also note that it's a foreign company being bought by another foreign company, and thusly you idiots have nothing to say on the matter. Further, DPW will only control 50% of the administration (and 0% of the security) of the port in question.