If you want an exchange with a Tobin Tax, then create one. Everyone who thinks it's a good idea will trade on it. Others won't unless you force them to. We'll then let people figure out how valuable HFT is.
Ugh. This isn't how laws work. I'm not suggesting it nicely and asking 'pretty please'. Government should, can and has been used to promote justice, equality and fairness. But only if people care to use it to do so. Trying to do everything outside of the system will result in failure. Nobody here has given me any rational reason as to why HFT is a good or moral or productive or beneficial thing. Therefore it should be stopped. This attitude of "I'm taking my toys and going home" does nobody any good, including yourself.