I had to think twice before including this film in my recommendations. Why? Well the language is atrocious and the subject matter controversial. If you've seen the satirical BBC sitcom, The Thick of It, you'll know what I mean, but on the plus side, you should learn some new vocabulary. The premise of the movie is that the US President and the Prime Minister of the UK fancy a war, but not everyone agrees that war is a good thing. When a mild-mannered minister inadvertently appears to back the war on prime-time television, he immediately attracts the attention of the PMs venomously aggressive communications chief Malcolm Tucker, who latches onto him like a hawk. Although played for laughs, the film shows how the most incidental factors (leaked papers, hastily spoken soundbites) and players (aides, interns, and low-level government officials) can influence the course of history.
!Note - If you're "in the loop" it means you're well informed about a situation.