"Some Republicans have minimized the significance of the disclosure of Ms. Wilson's identity, noting not only her working at C.I.A. headquarters but also the fact that she did not have an in-depth cover story: her purported employer, a shell company created by the agency, was little more than a Boston post office box." from:
Senate Panel to Examine Use of Cover by U.S. Spies.
So a p.o. box is just not sufficient for our national security? But a mailing address is all that it takes to evade American laws against trading with the "axis of evil". Remember Halliburton's "subsidiary" that let them evade the ban on trade with Iran?
"60 Minutes was expecting to find a bustling business, but, to our surprise, Walker told us that while Halliburton Products and Services was registered at this address, it was in name only. There is no actual office here or anywhere else in the Caymans. And there are no employees on site.
We were told that if mail for the Halliburton subsidiary comes to this address, they re-route it to Halliburton headquarters in Houston." from: Doing Business With The Enemy.
If a mailing address is good enough for Dick Cheney's company to sell to our enemies, a p.o. box seems plenty sufficient to help DEFEND ourselves from our enemies isn't it?