The quote that summarizes the thinking behind Hillary Clinton's strategy is here:
“The highest-premium voter in ’92 was a voter who would vote for one party some and for another party some,” said James Carville, Mr. Clinton’s chief strategist in 1992. “Now the highest-premium voter is somebody with a high probability to vote for you and low probability to turn out. That’s the golden list. And that’s a humongous change in basic strategic doctrine.”
The real question is whether this is a capitulation to the reality of a more polarized electorate or if it is just going to exacerbate this polarization. In either case, it seems like a reminder that Hillary is more pragmatic than idealistic, less about changing voters's minds than winning office.