The problem with Echalon-type programs today is cultural. They were/are intelligence operations. But today "intelligence" has grown to encompass criminal investigations and targeted, violent, operations such as drone strikes.
An intelligence operation does not need to be 100% accurate. Huge volumes of less-than-perfect data are examined by experts who then issue reports, opinions, on what is actually happening. The top report would be the sort of things included in a president's daily briefing. That was basic cold-war intelligence.
Today's leaders expect surveillance to be absolute. They don't want "and increased likelihood of attack", they want "Mr. Smith will be onboard flight 123 at 2pm". That's the level you need to send a bunch of cops to lawfully and publicly arrest a specific person and take them to a court for prosecution. Such things require very different methods, methods for which ECHALON was never designed.
> today "intelligence" has grown to encompass criminal investigations
That's a function of changed political objectives. "The enemy" became a liquid definition, purely for political reasons: "Arab terrorism" can easily be redefined as OLP or Taliban or Iran or AQ or IS or or or, keeping the public "at war" indefinitely and impeding scrutiny of reigning confusion in foreign policy. Until that stops, it's politically very difficult to fight calls for "more intelligence to stop our planes blowing up".
Unfortunately, the US (and EU allies, especially France and Britain) have now managed to screw up an entire continent so much, that a clear statement of interest to "reset" this state of things is almost impossible. In comparison, Vietnam and Cambodia were a walk in the park.
An intelligence operation does not need to be 100% accurate. Huge volumes of less-than-perfect data are examined by experts who then issue reports, opinions, on what is actually happening. The top report would be the sort of things included in a president's daily briefing. That was basic cold-war intelligence.
Today's leaders expect surveillance to be absolute. They don't want "and increased likelihood of attack", they want "Mr. Smith will be onboard flight 123 at 2pm". That's the level you need to send a bunch of cops to lawfully and publicly arrest a specific person and take them to a court for prosecution. Such things require very different methods, methods for which ECHALON was never designed.