Who could have foreseen it? (Oh, right, we did, months ago, when we described this year's appalling SCOTUS decision in Citzens United as "a case that would live in infamy.")
The following comes from Washington Post today (which, btw, doesn't bother to correct blatant errors in its reporting on other matters, but that's a different issue):
The $80 million spent so far by groups outside the Democratic and Republican parties dwarfs the $16 million spent at this point for the 2006 midterms. In that election, the vast majority of money - more than 90 percent - was disclosed along with donors' identities. This year, that figure has fallen to less than half of the total, according to data analyzed by The Washington Post.
The trends amount to a spending frenzy conducted largely in the shadows.
The bulk of the money is being spent by conservatives, who have swamped their Democratic-aligned competition by 7 to 1 in recent weeks.
...
The Supreme Court cleared the way for unlimited spending by corporations, unions and other interest groups on election ads in its 5 to 4 decision this year in Citizens United v. Federal Election Commission. Many interest groups are organized as nonprofits, which are not required to disclose their financial backing, helping fuel the increase in secret donors.