I disagree. The TSA has no mandate to determine intent - the organization was created to stop those with bad intent (and others) by enforcing regulations on all travelers. Maybe that isn't a good approach, and the high level goal is misaligned with the TSA's goal, but it is the current approach.

There was no epidemic of plane hijacking, either.

I have no data on the intent of people taking loaded firearms or black powder on planes (or knives in teddy bears,

Saying that 95% of people with bad intent can get through is unsupported by the statistic OP linked.

My point here is not that the TSA is great (I personally think it is pretty useless), but to suggest that single statistic is insufficient to demonstrate that the TSA is useless - you also need something indicating probably nothing bad would have happened had the TSA not confiscated all the currently banned stuff.

There absolutely was an epidemic of hijackings, in the 1970s. Then new laws were put in place banning weapons from planes.

That's the system that was in place up until 9/11, and it was run by private airport security. The TSA was a response to that.

But it wasn't the only conceivable response. Changes to private security screening rules would have been another option. The TSA isn't just there in a vacuum. And if people who try to sneak items past it can succeed, then its mandate isn't very effective.

Part of why another 9/11 hasn't happened is that terrrorists know that people know that hijackings can be very deadly. So people wouldn't be so passive anymore. The 9/11 hijacking was done with box cutters. That feat couldn't be repeated again, even with box cutters on the plane.

https://www.vox.com/2016/3/29/11326472/hijacking-airplanes-e...