Today’s must-read comes from OpenSecret’s Robert Maguire, writing an oped in today’s NYT:

Carolina Rising has no credible claim to being a social welfare organization. But the key thing to remember here is that Carolina Rising is not an outlier. It’s a trailblazer. In 2014, it was one of a new breed of politically active nonprofits that sprang up to assist a single candidate’s bid for a seat in Congress, with money from donors whose identities don’t have to be revealed.

The largest was the Kentucky Opportunity Coalition, which supported Republican Senator Mitch McConnell’s re-election with more than $8.2 million in reported political spending. Another group, Oklahomans for a Conservative Future, spent nearly $1.3 million backing the state legislator T. W. Shannon’s failed bid to be the Republican nominee for that state’s open Senate seat.

Carolina Rising is the first of these nonprofits to file a tax return covering the midterms. Yes, that’s history now, but this is the most recent info available; such groups don’t have to submit their returns until 11 months after the end of their fiscal year, so it’s impossible to track them in anything like real time.

But the document could be highly instructive for anyone paying attention to developments in campaign finance, including voters. It is also fair to wonder whether the Federal Election Commission and the I.R.S. will act to enforce existing laws. In recent years, the election agency has been frozen by partisan deadlock, and the I.R.S. has been cowed by Congress, while politically active groups have pushed through boundaries that once seemed impregnable, even in the opaque world of campaign finance.

Has Carolina Rising set the bar low enough for either the F.E.C. or the I.R.S. to say, finally, that enough is enough?