The effect of money on campaign outcomes is what he was speaking in reference to - a lot of lobbying money ends up getting funneled directly into candidates pockets through advantageous deals and future employment promises as well as undercharged services (like renoing someone's house for a few dollars) and that money can be quite significant.
I think that Politics is naturally self-corrupting but the extreme partisan divide in America has, IMO, made politicians less vulnerable to the crap they tread in. There is very little you can do to make yourself less desirable than someone on the other team so corruption is really only an issue for being primaried and toeing the party line can still protect you pretty effectively.
America has an insane bribery problem.