Well considering they are funding Obama's campaign, having their employees work 'as volunteers' for Obama... I would say VERY POWERFUL.

The robber Barons all support Obama. The small business, the medium business, the the fiscally conservative are reluctantly backing McCain...

btw McCain despite saying he is a 'deregulator' has a history of regulating all sorts of things.

I think economic elites are very powerfull in politics.
When you look at Bush administration you see he is all in the hands of arms and oil industry.
Thats politics.. you have people supporting your campaign.. and for sure they expect something back in return.
Its like this all over the world i guess... maybe in america where presidential candidates are way more dependant on supporters donations its a lil more extreme then in europe.

Money means influence.
thats life, even if you are a socialist.

the political system of the US is based on money. after more than 200 years of elections this fact never changed. election campaigns are and were expensive in such a wide nation. in former times candidates traveled around by ship, horse, in trains, after that by plane. than they needed presence in the press, radio, TV and now in the www. candidates needed money for that. their first steps were often financed by themselves, but with success in their campaigns they needed far more money, so they sell/sold themselves to lobby groups. this political style seems to be accepted by the population in the US. in germany this would not be possible in such a dimension. it is called "corruption" here and is a crime.