There is probably no action that is totally immune from all types of congressional conflict. However, that is beside the point: there are hundreds of thousands of investments that are NOT affected by Congress.
Until we know the actual investments that Romney and Obama have in the Cayman Islands, there is absolutely no way to consider them equal in size or purpose.
It is rather unlikely that the Illinois legislature has a program involving investments in the Caymans.
There are a few mutual funds that are open to European investors,but not to American citizens (because they do not comply with the reporting regulations for mutual funds) that I have heard are available from Cayman Islands brokers.
Somehow I got on this stupid email list that touted overseas investments, was always warning about a total global collapse, and nonetheless, had a US flag on nearly every page. They were always talking about some magnificent opportunity to
make money, and never said a word about avoiding taxes.