http://www.richw.org/dualcit/faq.html#recog
Are there any disadvantages to dual US/other citizenship?
Aside from the possibility that one or the other country might decide to impose distasteful restrictions on you because they consider you to be one of their citizens, there are at least two issues that you might (or might not) see as causes for concern.
If your line of work requires you to have a security clearance for accessing classified US government information, you may very possibly find that actively acquiring or retaining a foreign citizenship may cause you to be refused clearance (or may cause a clearance you already have to be revoked). If this might affect you, you would be well advised to consult with a knowledgeable lawyer.
If you are seriously planning to seek a political office in the US — especially in the federal government — it is extremely possible that having a second citizenship may be a serious liability. Your opponent will almost certainly be sorely tempted to (mis)represent your status for his/her own political gain — questioning your loyalty to the US and your suitability for office — and any efforts on your part to explain or justify your situation are likely to fall on deaf ears. This is less likely to be an issue if you are running for a state or local office.
Line of work. Hmmm. Like having your finger on the Nations nuclear button, and having the Armed Forces under your control?
Commander in Chief is a job, isn't it?
I'm pretty sure GW Bush gets a paycheck.