According to Forbes, starting with FDR, the three richest modern day presidents have been FDR, JFK, and LBJ. John Kerry is richer than all but JFK. John Kerry with John Edwards as a running mate may be the richest president/vice-president ticket of all time.
It's amusing to me that all of these very rich presidents are democrats. Why would these spectacularly rich people end up being champions for the common man? Indeed, it seems to me that it would be difficult for them to even to relate to the common man. How would they know what the poor and lower middle class really want for themselves and their children?
My more cynical view is that, like everybody else, their motives were selfish. Since they were already rich and had every material thing they could possibly want, they wanted to further increase their status. They way to do so is to prevent anyone else from becoming rich. The way you do that is to tax high income. It has always struck me that rich-guy populists never propose taxes on wealth. They only propose increasing taxes on high income earners - the exact class of people who might become wealthy and dilute the status of the already rich. Having a high income is not the same as being wealthy.
When they propose a wealth tax of 5% per year on everything over $10M in net assets and 10% per year on everything over $50M in net assets, then I'll believe them when they say they want to "tax the rich."