Is it guaranteed that the coalition of voters that propelled Obama to victory twice will come out in full force again in two years, though?
I followed this election exclusively on CNN and maybe they will be proven wrong, but at some point both Republican and Democratic pundits said it's conceivable that a sizable chunk of the voters that made the difference in 2008 and 2012 (i.e. young voters, minorities, women) are mainly loyal to Obama and not to the Democratic Party. The conclusion was that with someone else leading the Democratic ticket in 2016, many of them simply might not show up to vote.
Agreed. Turnout will be up and it will be up disproportionately among the Obama coalition, but without Obama it a) won't go up enough for the Dem to match '08/'12 and b) will include a lot of younger people who will be open to voting for a non-insane Republican. Hillary Clinton certainly can't summon up the Obama coalition with Obama strength; Dems have to hope that she takes a chunk out of the Republican anti-Obama coalition.