Vox has been compiling a list of all of Trump's known conflicts of interest. It prompted me to a thought experiment wondering if corporate involvement in foreign economies doesn't cancel out at some point.
Consider a President who was secretly completely motivated by personal greed. If that President had 1 foreign investment, that 1 investment would determine his actions whenever they were threatened (or, inversely, could be grown). That's an obvious problem for us as Americans.
If he has more than one, however, there might be at least some cases when there are opportunity costs. Taking this action would benefit that investment, whereas the alternative action would benefit another. There might be important facts about the size of the investment that would rule, but the overall effect of multiple conflicts of interest is to reduce the power of each on his decision-making process if (and only if) they conflict.
With a small enough set of foreign investments, such conflicts should be rare. However, as the set grows, conflicts become more frequent. An adequately diversified President, even the totally corrupt one of the thought experiment, might eventually be as unmoved by his conflicts of interest as a president with no foreign investments at all.
This isn't to defend Trump, whom I think really should take seriously the conflicts-of-interest problem. It's just interesting to realize that adding many new ones doesn't make the situation worse: arguably, it makes the situation better.