Clinton donors say Sanders is raising more than the front-runner

[Jim Lane]

8. My guess as to the explanation

First, you refer to Clinton's SuperPACs. The linked article isn't clear on the point but I strongly suspect that it's comparing fundraising by each campaign directly, excluding any SuperPAC money (of which Clinton has a pile and Sanders has none).

Second, note that the comparison isn't even overall fundraising by the campaigns. It's the projection for campaign fundraising in the final quarter of 2015. Clinton has been running for the 2016 nomination since mid-2008, but Sanders was much later to the party. Clinton worked many of her donors earlier than Sanders did. That leaves him more room to grow in the later reporting periods but doesn't mean he has an overall advantage. I strongly suspect that total campaign fundraising through the end of 2015 (not just the final quarter) will show Clinton well ahead.

Third, a factor noted in the linked article is that Clinton has a complacency problem -- not that she personally is complacent, but that some prospective donors are. They think she has a lock on the nomination. Why should they fork over money just to help her run up the score? On this theory, if Sanders does manage to win both Iowa and New Hampshire, quite a few new donors would flock to Clinton's banner, and old ones would cough up more (if not maxed out), because they would suddenly perceive that there really was a threat. (Of course, such a 1-2 punch for Sanders would also get him a big boost in donations.)