Reply #101: money, and even more than donations, jobs when they leave office as lobbyists, CEO's, and

[yurbud]

board members.

Voters at least used to be able to compete a bit in donations before Citizens United, but we could NEVER compete in the jobs after they leave office department (or jobs to spouses and kids even while in office).

This article is a good primer on the corporate wing of the Democratic Party. The specific organization no longer exists, but its members still operate the same way:
http://prospect.org/cs/articles?article=how_the_dlc_does_it

It also isn't as much Dems chasing the money as the money placing their people in the process. If a Republican can't win in a certain district or state, business people don't just sit in a corner and cry, they find someone to run as a Dem who will follow their orders. Unfortunately, they have done the same thing with center-left parties in other parts of the world like Britain and New Zealand. People vote for the Labor Party and somehow end up getting conservative austerity policies anyway.

Tony Blair
http://www.dlc.org/ndol_ci.cfm?kaid=128&subid=187&contentid=499

New Zealand
http://en.wikipedia.org/wiki/New_Zealand_Labour_Party

Groups like this are like astroturf issues groups: they look independent, but are wholly owned by certain corporate interests.