is somewhat lengthy but worthwhile. It discusses how employees are "asked" to contribute to campaigns and organzizations favored by the higher ups.
On Wall Street this has favored Republicans. In fact, this article is great insight into GWB's Rangers. Unions do a sort of similar thing that is controversial by withholding funds from paychecks.
I'm not sure what the right answer is campaign finance reform. I just know that the current laws leave much to be desired despite some real attempts at reform.