How can foreigners be prevented from trading? Punishment after the fact won’t work for many reasons.
Don't know. I leave that to people who know a heck of a lot more about it than me... but how about, for starters, forbidding floor traders and US-based brokers from accepting trades from overseas accounts?
Not trying to punish anyone after the fact (though the courts do that all the time), I'm just trying to figure out how to prevent terrorists from continuing what Cramer says they're doing, or prevent them from doing something worse in the future.