Some people insist that new terror tactics show the need for heightened security. The bad guys are constantly brainstorming new ways to kill people, we need to prevent them from killing people, and so let's make people take off more of their clothing at security checkpoints. That's not incoherent. It's a little bit paint-by-numbers, but it's not incoherent.
The alternative is to suggest that while we certainly do need to stay ahead of new terror plots, TSA doesn't seem up to the challenge. Instead the agency is always trying to protect us tomorrow from yesterday's threats. This is an a perspective we have sketched on more than a few occasions. What's the point of having TSA look for old bomb designs, if the terrorists are creating new bomb designs?
Now in this case, it seems like the threats being discussed - shoe bombs and toothpaste explosives - are actually old threats that TSA should be able to detect (how many ways can there possibly be to design a shoe bomb?). So maybe this will become a case where the agency declares that its security measures are working as planned.
But how confident are you that the terrorists aren't creating new kinds of shoe bombs exactly with the TSA's current methods in mind?