I don't know if worldwide events influenced his selection of if poll numbers did, but he doesn't seem to fit. Just not quite right.
Update -- As if to prove my point:
Biden has accepted $5,133,072 in contributions from lawyers and lobbyists since 2003. Obama does not accept contributions from federally registered lobbyists.Hot Air
And he has one other weakness that hasn’t received much attention to date. One of Biden’s sons, Hunter, is a registered Washington lobbyist in a year in which Obama has been excoriating lobbyists and the culture of corruption in Washington. The younger Biden is a name partner at the firm Oldaker, Biden & Belair, LLP, and seems to have specialized in lobbying for just the kind of earmark spending by Congress that Obama has vowed to slash. Republican insiders say the party is likely to make an issue of Biden’s family lobbying ties.
Also expect to hear more about Biden’s close ties with credit card companies. His largest contributor (based on total contributions by employees) over the past five years has been MBNA, the Delaware-based bank aquired in 2005 by Bank of America than until then was the world’s largest independent credit card issuer and a major supporter of the 2005 bankruptcy bill that Biden crossed the aisle to support.