It seems the U.S. as an entirely abstracted political term and entity (as in, "the government") still does incorporate the interests of national and multinational companies performing business transactions within and outside its borders with other similarly acting "abstracted political term[s] and entities" and persons into its foreign policy. It seems, furthermore, not only considerations with at least directly related economic concerns are motivating factors determining its foreign policy, even when unrelated to international and national trade according to strict understandings of the term "trade". Frequently, this is how any number of presenting entities might also act, with and without cultural, economic, political and social tenets and traction from which to draw reasonably related interests and involvements, however much impacting in the negative or positive for any number of similarly classifiable entities, foreign and otherwise.
At the end of the day, the corrupt people who run the United States are no better than the corrupt people that run any other country. These leaders will do what they have to do in order to stay in power and collect their money. They don't care about democracy, they care about their profits.
I think that this is the crucial argument against having, or even appearing to have, any conflicts of interest with respect to business and policy. The president and other heads of state are first and foremost policy makers, enacting laws for the citizens of their country. If they are in any way influenced by company interests, they may craft policy that benefits industry to the detriment of the public.
Unless there a circumstances we are unaware of, I'm not familiar with any cases like this in recent memory. That's not to say that foreign policy isn't driven by strategic interests such as energy resources, but individual companies do not warrant intervention from the U.S. government. I'm sure, however, that intelligence agencies have propped up certain American companies operating abroad for espionage purposes, but I don't think that's what this question is really asking.