This letter from Sanders’ lawyer Brad Deutsch (and see this accompanying press release) say there are some “serious apparent violations” of campaign finance law. I’m not so sure that’s right, and suspect this letter is less about legality and more about feeding into the Sanders’ campaign theme that Hillary Clinton is corrupt in her campaign finance dealings.
Here’s the deal. Clinton, like Sanders and other presidential candidates, has set up a joint fundraising committee with her political party. The JFC allows you to raise a huge chunk of change (more now than in past campaigns, thanks to the Supreme Court blowing out the aggregate federal limits in the McCutcheon case). A small bit goes to the candidate’s committee under the federal limits (currently $2,700 for the primary and $2,700 for the general). The next bit goes to the DNC, and the rest so state parties in $10,000 chunks. Sanders is accusing the joint committee of raising really big donations, and then having the JFC using some of those really big donations to engage in direct mail and internet targeting of small donors. When those small donors donate small amounts, contributions up to the first $2,700 benefit Clinton under the JFC agreement, and because these are small donors, it means Clinton gets all that small donor money.
The Deutsch letter cites no authority showing that this use of the JFC is not allowed, and it is hard to see what provision of the law it violates when donors give only small amounts that happen to benefit only Clinton. The letter says that maybe this is like an in-kind contribution from the DNC to the Clinton campaign, but I don’t see how it is that if the money is coming from the JFC not from the committee. The letter even says this means that those giving big checks to the DNC might thereby be giving more than the $2,700 to Clinton, which is not literally true—it is what the JFC is doing with the money, over which the donors have no control.
So legally this seems weak.
And politically, it is quite odd for Sanders, who would need the DNC’s support to win the presidency should be be the Democratic nominee, to be attacking the DNC. (Then again, Trump has relentlessly attacked the RNC, so this must be the celebration of the season.)