Money in politics is a major story in the 2016 campaign. Here are 3 big open questions.

It's now six years since Citizens United and related decisions ushered campaign finance into the Super PAC era. Things certainly feel different. And money in politics will probably continue to be a huge story in this election, since not only is it a kind of big deal, but also the steady release of fundraising numbers lends itself to the easy-to-produce, tick-tock, score-keeping kind of coverage.