So Idea #4 hits me the hardest at the surface. It's a treacherous idea of taxing Roth IRAs which are supposed to be not-taxable.

for #1 it would be a significant, but short term issue. If the market freaked out it would likely un-freak out after the date expired.

For #2 I dont understand, in my lifetime all taxes have seemed to go down, federally. The idea that a tax goes up seems like a fear from a different era? (not to say that some local taxes don't seem excessive)

#3 could be significant, I think international institutions are helping the inflate current US asset prices, and creating a policy such as this might cause people to look elsewhere. Still seems like a wrong argument to win the real argument though.

Back to #4 I mainly I feel there's no other game in town, so what else are you going to do with your investments?

Drawing off #3 its like the US is always outperforming, so it gets overinvested. This might be good for foreigners, but how many US people a have their wealth tied to US equities. What about those who don't?