I'll agree with Slowguy on this one.

Example A) Politician says trees are good and I will do what I can to support them. Sierra Club give them money.

Example B) Sierra Club give politician money and expects them to return the favor by supporting trees.

A is how things are supposed to work and B is corruption. Without a smoking gun, how can you really tell the difference?

What do you mean by "lobbyist money?"

Is anyone who has an interest and donates money a "lobbyist?"

Or do you mean actual registered lobbyists?

I think you're being vastly overly broad. We have laws that allow giving money as a form of speech. If you're going to assume that anyone who accepts money from someone with a political agenda has therefore arranged an explicit quid pro quo contract, then I guess you'd conclude that they're all corrupt. But that's kind of a stretch.

My Congressman is a former Marine. He gets lots of donations from Lockheed, General Dynamics, etc. Are those contractors just supporting someone they feel understands and supports their interests and can articulate them well to Congress? Or has he arranged explicitly to steer DoD contracts to them?

If you want to see corruption everywhere, it's not hard to think that you do.

Running for any office costs money. You have to get funds from somewhere.

They just went through a presidential election in the Philippines and the contrast with here is interesting. People often say those countries are very corrupt, and they are, but the corruption exists here too, just in a different form.

There, all elected officials, from the local area, to major, to governor and up to the President pay cash in return for votes. It is illegal to pay but also illegal to accept payments but since both sides do it, no one has an incentive to report it. I was there in my home when a local man, representing the incumbent mayor, knocked on the door on election night and gave an envelope of cash to my girlfriend. He simply said that this is from the mayor and was ready to walk away. She called him back and returned the envelope and said her vote is not for sale and he walked off. Every neighbor I spoke with accepted the money, without any hint that there was anything wrong. The amount in the envelope, for the 1 mayor candidate was about $10 US. The same process can occur with the other candidates, and also the candidates for city councillors. Some people can "earn" about $100 on election night. It is how democracy works in a large part of the world (I saw the same in Thailand).

Here, it is more discreet with some politicians doing favors, pressing tax legislation, lobbying , giving permits/licenses etc., and typically goes on behind closed doors.

I find the contrast interesting because we tend to think the countries with more direct forms of corruption are far more corrupt but I'm not so sure.

And if supporting trees is what you want, then why would you care?

You don't really believe that she earned close to Billy because of her vast experience in government do you? She was paid to "speak" because a lot of companies (see Wall Street) are betting she will be the next President. By paying her to speak they can buy influence before she even gets in the White House. Wonderful system we have isn't it?