Only considering national elections, politicians need a minimum of one million dollars to run a campaign for congress. That is big money and big money these days means Wall Street, the big banks and Wall Street investors that have gotten rich in that environment. Accumulation of small campaign donations typically will not come even close to adding up to the money needed for a national bid today.
No, I do not believe that a politician, American or otherwise, can go without big business on their side. It is a known fact, even if everyone wants to turn their heads, that big business runs countries. In reality this is true all over the world. If corporate American wants a certain person to be in office, it will happen.
I do not believe an American politician can win without having Wall Street on their side. I wouldn't believe it was possible until someone proved that theory otherwise. Generally, in the US, the winner seems to be the candidate with the most funds and generally that money comes from corporations.
A politician running for political office can win without having Wall Street on their side. Wall street finance does not vote in an election people do, and the majority of people do not live like Wall Street brokers. Many politicians have won without the support of Wall Street, Obama would be a prime example of that.
An American politician cannot win without having Wall Street on their side. This is because finance is at the heart of daily life in America. If a politician is bad for business expansion, for example, he or she will not win office. The opponent will likely receive a lot of donations.