Will a single-issue Democratic primary candidate rise to the top?

[MineralMan]

19. Well, I think too much focus on a particular issue can

hold a candidate back in a serious way. Elizabeth Warren is doing OK and rising in the polls. She's not actually a single-issue candidate at all. In fact, she has position papers and plans for a wide range of issues, and I believe that's why she's doing well right now.

Inslee focuses hard on the climate change issue, and is stuck at 1% or less in the polls.

That doesn't mean that Inslee does not have supporters. He does. It's just that voters have their own issue priorities and tend to make choices based on those, as well. If one candidate's highest priority issue doesn't match, they look elsewhere.

Which is not to say that climate change is not a crucial issue. It's just not the only crucial issue in this election year. Pretty much all of the Democratic primary candidates take climate change very seriously, but most of them also have positions on multiple issues that are of concern to voters. That seems to me to be a more effective campaign strategy for a presidential candidate.