Why aren't email scams (spam) illegal?

Am I the only person who thinks people who blatantly try to con people out of money should be stopped and punished? Most are successfully filtered out, but I still get them from people who've "inherited a fortune" and need to find a mug to launder it for them, and from people pretending to be legitimate businesses (banks etc) asking for my marital status, bank account details, address, ID card number etc. Surely this shouldn't be legal! Why aren't they being tracked down and stopped?!