Amid all the scandal around the World Bank boss, Paul Wolfowitz and his (required/demanded/expected, by most) would or would not-be resignation, here's a very recent leaked memo from him to his staff (Ken Rogoff has been rather careless and leaked it to the press :-)). One of the best parts is the following: "Some of you may also wonder whether World Bank staff, directors, or presidents are permitted to buy “George W. Bush Impeachment” contracts, which are also presently listed on TradeSports.com. Tricky question, but the bottom line is that your employment generally precludes political activity of this type. You will be relieved to know, however, that I have already instructed the Bank legal staff to allow exceptions to the insider trading rules for anyone who can demonstrate a truly compelling need to hedge against a change at the White House."
So, if you can demonstrate a truly compelling need to hedge against a change, you've got the green light (even if you're not a World Bank employee...). I assume it also works for far less known- second class, really- actors like Romania and its (currently suspended) President, though, curiously, nobody thought of listing "Basescu Impeachment" contracts on the Intrade.com (by comparison, Russia's 2008 elections are already in!).
I found out about the "memo leak" from Greg Mankiw.