Four years ago today, when Sen. John McCain of Arizona confirmed that he had picked Alaska Gov. Sarah Palin to be his vice presidential running mate, the reaction across the country – indeed, in many newsrooms – was about the same: "Sarah Who?" Not so when
Mitt Romney added Rep. Paul Ryan to this year's ticket. And their easily apparent differences aside, the entries of Palin in 2008, and Ryan this season have added strikingly similar dynamics to their respective races.