In contemplating how Biden's entry might impact 2016's primary dynamics, it's worth reviewing how he and Clinton operated together in Obama's first term. While each can plausibly argue that they would represent a continuation of the Obama administration into a "third term", enough has been written at this point to indicate that there is serious daylight between a potential Biden administration and a Clinton one.
I'd encourage everyone to take a look at these three articles, published in 2014 and 2015, that reveal marked differences between the two on foreign policy and diplomacy in particular:
The Nation: "The Left Ought to Worry About Hillary Clinton, Hawk and Militarist, in 2016" Vox: "Biden's the dove and Hillary's the hawk on foreign policy" Politico: "Was Biden right?"We've already seen in the past week strong evidence that Hillary Clinton is pivoting to the right (or the "moderate" "center" per PR-approved language), and intends to strongly differentiate herself from Obama's soft-power war-averse foreign policy. It is increasingly likely she'll be running away from Obama's legacy in some areas, specifically national security.
While Joe Biden was, like Clinton, justifiably criticized in the 2008 primaries for his Iraq War vote, there's considerable evidence that he was the most cautious adviser in Obama's inner circle on the use of force abroad. Perhaps part of this was the fact that he had a highly-decorated son who served in Iraq, and arguably no other candidate can better make the case for the human cost of military engagement. His opinion is largely unimpeachable on this front.
Move past the orange swirl below for some takeaways from the Nation, Vox and Politico articles above.