Barack Obama has really found in the form of the internet, a new source of funding that overwhelms the previous political funding model. I have not seen much discussion about this, but Bill Clinton's median campaign dollar, likely came from a source that was relatively sympathetic to Israel. (Meaning if he collected $60 million, then put the contributors in a spectrum from most to least sympathetic to Israel, count from either side, and choose the contributor who gave the contribution that put him over $30 million.)
Jewish Americans, the US' single most wealthy ethnic group, was during Clinton's time by far the most wealthy segment of the Democratic coalition that Clinton, Gore or Kerry would have needed to win election.
Obama had vastly outsized contributions by African Americans supporting the exciting prospect of another African American with a realistic chance of winning. He also had, through the internet, a more effective way to extract money from a young urban cosmopolitan demographic that contains Jewish people but not is not nearly as disproportionately Jewish as Clinton's support base.
Contrary to Bill Clinton's, Barack Obama's median campaign dollar likely came from a donor less invested in the continuance of a Jewish state, or less willing to accept or justify misery imposed on others such as the Palestinians as necessary for the greater goal of Israel's security even than Obama himself is. There is no pro-Israel donor who can credibly say to Barack Obama that without the viewpoint I represent, you cannot amass the resources necessary to win election.
This possibly marks a structural change in US politics.