You could make insider trading legal by law, but that would destroy a lot of the stock market because all non-insiders would basically set themselves up to be ripped off.

No, it wouldn't destroy the stock market. See https://news.ycombinator.com/item?id=43661926 for an explanation.

Summary: people are already allowed to trade on inside information (in the US), if the person who officially owns the information is ok with that. The prohibition on insider trading in the US is about fiduciary duty to the owner of the information, not about protecting the general public.

> So there are lots of things that have long been legal in the US that would have been illegal in France, without the economy collapsing.

Who knows, maybe we are in the middle of the resulting collapse now ;-)

Well, that collapse is because of tariffs, not the intricacies of differences in insider trading law.

I was thinking more that these kind of lax laws allowed the rich to get richer, and influence politics in ways which enabled or accelerated the fall. But it it a complicated picture of course, and the further back in the chain of causality we go the harder it it to say anything for real.

> [...] allowed the rich to get richer, and influence politics [...]

That would have been a better world than the one we live in.

I'd rather have Romney and Bloomberg etc than the populists we got.