[toast0]

Two things:

1) Most of the spam calls are spoofing numbers, so it doesn't really matter who issued the numbers.

2) Spam calls could come from overseas numbers instead, I've certainly gotten a few. I'd rather they come from US numbers, so at least when people call back, they're not paying an arm and a leg for the call if they don't realize the number is non-US.

[zenexer]

#1 is a key point here, and understanding it is essential to solving this problem once and for all. It's not just caller ID that they're spoofing. PSTN works a bit like the internet: there are "good faith" peering agreements between telephone companies, and they rely on each other to report truthfully where a call is coming from.

However, there are many companies, especially overseas, that either deliberately shirk these duties or simply lack the funds, technology, and infrastructure to authenticate the sources of telephone calls. The result is something akin to IP address spoofing.

Without imposing major infrastructure overhauls on foreign nations, there's little the US government can do to eliminate these problems.

[GordonS]

Here in the UK, nowadays almost all robocalls and scam calls are coming from outside the UK. Mostly India as far as I can tell (they've sworn at me in Hindi).