Washington Post columnist Anne Applebaum has a very good piece on the folly of the US to creat a list of "critical infrastructure" where the items on the list will be offlimits to foriegn investors.
Indeed, though it may appear to be counter-intuitive, the US really ought to encourage foreigners -- especially those who pose potential threats to US security -- to invest in US assets. If that means giving them tax breaks as inducements, such insurance premium would be dirt cheap in comparison with the trillions of dollars being spent on homeland security.
Things contained in the list are critical assets right? They are designated as critical supposedly because they will be the first targets enemies will pick when they plan to attack the US right?
If that is the case, you should prefer those assets to be owned by the very opponents of the US who are contemplating to attack the US in general and those assets in the list in particular.
Doing so raises the price of attacking those very assets and with demand curve for attack slopes downward, need I say more?