Political Speech a Crime

When is political speech actually disorderly conduct? While this does not directly relate to the conflict with Iran, it certainly is an issue because anytime we talk about war and peace, political speech is involved. Dr. Wenyi Wang shouted out to President Bush not to let President Hu continue persecuting Falun Gong/Falun Dafa. Later, she was charged with disorderly conduct, and is awaiting further charges, still in custody. Dr. Wang was clearly not trespassing (she had press credentials), and was clearly exercising political speech. How can she be charged with disorderly conduct for clearly political speech? My guess is that they can charge her with anything they want, but that it won't fly in court. In other words, it is a form of intimidation (one that we hear a lot about) from the executive branch, but the judiciary will come down on the side of free speech, in a case this clear. Still, it would seem it has a chilling effect on free speech. Since when are you arrested and charged in the US for voicing your opinion to a public official? As we gear up for potentially more anti-war protests if the conflict in Iran deepens, this is something for the public to be aware of. Your thoughts on this are appreciated. If Britney Spears can say and do what she wants, why can't Wenyi Wang?