Talking Points Memo had this. I'm merely raising it over here and adding some personal observations.
There has been a lot of concern about threats shouted at McCain/Palin rallies. Some folks are worried that the United States Secret Service might be nappin' on the job.
Well, check it out at the Scranton Times (or TPM, if you like). http://www.scrantontimes.com/... The United States Secret Service (USSS) is indeed on the prowl and if the individual who made that threat is identified, he will be entering a world of discomfort.
I've had several professional encounters with the USSS when I was serving an internship with the VA in Texas. Many veterans were unhappy with Ronald Reagan (imagine that!) and some of them ignored the sign above the intake window that promised meetings with the USSS if threats were made. When they said words to the effect that "I'm going to kill that SOB," we called the local office of the USSS and told them we had another one for them. They were extremely good at what they did. They just knew who's blowing smoke and who's a serious threat.
Some years later, I was picketing a visiting person that I didn't care much for. A member of the USSS came up to me, addressed me by name and informed me of what the rules were that day. It was mostly stuff like what size the wood on our signs could be and not to extend them over the restraining rope. Other than that, have a good time. Very professional and I was impressed that she knew my name.
I've since had the pleasure of meeting a retired member of the USSS. He's just incredibly smart and was very good at what he did. At least one ex-President reached a ripe old age due to his actions.
These folks are extremely good at what they do. They are the best in the business. While they can't prevent everything, if they find out you're yelling about killing a "protectee" you can bet your house (not much of a bet these days, but hey...) they will find you.