Until he announced his immigration policy last week, Obama had the support of most Hispanic voters - but not the enthusiasm they had shown for him in 2008. That may be changing in part because of the decision not to deport young immigrants whose undocumented parents brought them here as children.

Hillary Clinton is also not a very exciting, inspiring candidate to a lot of the left-leaning Democratic base, especially in Iowa.

Obama has built his public image around his ability to bridge divisions - racial, ideological or generational. And that was his reputation, even at Harvard Law School, where he was the first black president of the 'Law Review.

Obama's even keel sometimes comes across as aloof or even cold.

The establishment is divorcing itself from its base - from voters who are choosing a candidate who says he stands for things that are anathema to the establishment.

In 2012, African-Americans were 13 percent of the electorate, and 93 percent of them voted for [Barack] Obama.

[Mike] Bloomberg aides says he's more likely to run if it's [Donald]Trump or [Ted] Cruz versus Sanders, then there would, presumably, be space in the middle for him. But he's less likely to go if Hillary Clinton is the nominee.