Ran? No. Heavily influenced? Yes.
EDIT: I should elaborate on this.
Like it or not, the people who run the US government are politicians, and I firmly believe that the majority is upright about it. There are always some black sheep who are in it only for power and money, but the majority have dedicated their lives to the American democracy, Democrat or Republican. Some of them have their own particular views of what is best for their country, and these views may not be shared by the rest of the political scene - or the rest of the world for that matter. But I don't doubt that they are upright about it.
However, there comes a moment in the life of most politicians, where they have to compromise. That is no different in the US, in Germany, in Croatia or anywhere else. Most politicians have some goals and views they put above others. Someone who devotes their life to fighting social injustice might not, for example, be very interested in environmental issues. They might have formulated a view on the matter, but it is not very interesting for them to pursue it, so they leave that for others. Keep that in mind.
Now, the US is a huge country -both geographically and population-wise-, and there is a comparatively big number of people who are interested in politics. It is really confusing for a non-American to get so much as an overview over what there is for an American to vote for. But one thing is important: If you want to become a high-ranking politician, you need to get your face known. You need to travel the country, be it your state or the entire nation. You need to talk to the people everywhere, in every big city and preferably some small ones as well. You need to show the people that you command a team of trustworthy individuals who will put your ideas into action, and you need to send them across the country too. All this costs a lot of money. Even those politicians from rich families who have been influential politicians for generations, such as the Kennedys or the Bushes don't have enough money for such a campaign. So they need supporters. Those supporters are usually private people or companies, and yes, their intent is to have a say when the politician gets elected. They form lobbies.
The politicians need those lobbies for their time in office and future campaigns. That doesn't mean they want the money. They want the support, because you can't make politics without support. So when it comes to issues the lobbies are interested in, the politicians will try to rule things favourably for them. Usually, those are either issues the politician agrees with in the first place, or that don't interest him very much. There are of course cases in which the politician is prevented from reaching his initial goal because the lobbies were against it, but I don't really think those are particularly numerous. Most politicians will choose their supporters on the grounds that they can still achieve their goals once they're in power.
Incidentally, the lobbies themselves aren't inherently evil. Most are simply interest groups that have certain goals they want to achieve - and of course those can be arms deals, but they can also be environmental or social issues; you cannot put a sticker on every lobby, you need to judge from case to case.
As a European, I think the lobbies can be a flaw in the American system, but I nevertheless don't think they always have to be. And I have also yet to hear a good alternative on how to run such a huge country with democratic methods.
Looks like you got us all there. You certainly did fool me for a while. 
