Bruce Schneier, who is on the working group evaluating the security and privacy implications of the US Secure Flight passenger screening program, is very critical of the expanding scope of the program is his latest Cryptogram.
He also has a perspective on the London's Metropolitan Police shoot-to-kill policy when dealing with suspected suicide terrorists.
"The London police are now sorry they accidentally killed an innocent they suspected of being a suicide bomber, but I can certainly understand the mistake. In the end, the best solution is to train police officers and then leave the decision to them. But honestly, policies that are more likely to result in living incarcerated suspects who can be interrogated are better than policies that are more likely to result in corpses, especially when most suspects will be found innocent."
Lot's more besides, Cryptogram is always a good read.