Democrats' 2020 race has a new shadow: Hillary Clinton

Hillary Clinton is popping up in presidential politics again, and some Democrats are wary even as they praise her role as a senior party leader

Her scuffle with Gabbard and other recent headlines she's driven demonstrate that the 71-year-old remains a political lightning rod, just as she's been through much of the last three decades. The dynamics raise questions about how Clinton and her party can best leverage her strengths and navigate her weaknesses through next November.

For her part, aides say Clinton isn't attempting any calculated play.

Clinton spokesman Nick Merrill says, "The short of it is that she's on a book tour and is feeling unconstrained about speaking her mind."