You want to spend hundreds of billions of dollars on a national system to counteract the threat of determined attackers that is ineffective against determined attackers?

Building an effective IED that can be transported by a drone is already much harder than bypassing any realistic national anti drone defense. Who is this system mean to stop?

>A good point. I think flying above 400 ft is already illegal though, so dealing with that might be somewhat simplified.

We are talking about determined attackers, so it being illegal isn't really relevant. Unless you want to cover the country in radar that can track anything the size of a drone that’s above 400’, so the camera system on has to handle below 400’. That’s possible, but now we’re adding hundreds of billions more to the system.

>just as bridge toll systems now often use license plates to track fees. It's not all that hard in this day and age.

Bridge toll systems are nothing like the proposed system. There is a huge difference between building a camera that takes pictures of license plate that sends a ticket in the mail weeks later, and a distributed system with hundreds of thousands of access points that each need to access a national database to make decisions in real time.

>We don't expect red-light cameras to pull us over, but we do expect they do something. It's not crazy to expect they also might have specific circumstances that flag to additional review for possible dispatch of an officer.

Red light cameras don’t do anything like this at all. The amount of false positives is far too high. There is a reason you get a ticket in the mail weeks later.

> If you see six objects and receive 5 signals, eliminate the ones you can, and send someone to investigate with directional equipment.

Drone flight times are usually under 20 min. Even in the future with battery technology, it’s unlikely someone is still going to be operating by the time you get someone out there with directional equipment. And now we have a to train a nationwide drone force capable of operating directional equipment.

>You make the sale of fake license plates illegal, you make sure the only valid plates are issued by the government, and you make it illegal to tamper with them.

None of these will dissuade a determined attacker. Just like license plates don’t stop terrorists. They aren’t designed to do that.

>Already covered a little above, but there's already solutions appearing to help with this. There's anti-drone ammunition[1] and trained animals[2] on the simple end, up to military grade anti-drone solutions.

So anytime a transponder malfunctions you want to shoot at a drone over a populated area? You want to want to add gun turrets to the cameras covering the country? Or do you want a nationwide system of trained attack birds stationed every mile or so?

You are massively underestimating the difficulty to accomplish what you are proposing.

The amount of explosives a drone can carry mean that for the foreseeable future they aren’t going to be particularly effective weapons for terrorists. Certainly not effective enough for us to spend hundreds of billions of dollars on a system that can be easily bypassed by flying below the tree line.