Top 10 US Senate races, by money spent Seat Incumbent Party State Overall Spending* Kay R. Hagan Democrat North Carolina $107,611,734 Mark Udall Democrat Colorado $93,105,867 Tom Harkin (open) Democrat Iowa $82,519,557 Mitch McConnell Republican Kentucky $76,730,485 Saxby Chambliss (open) Republican Georgia $67,008,695 Mark Begich Democrat Alaska $56,895,627 Mark L. Pryor Democrat Arkansas $56,139,229 Carl Levin (open) Democrat Michigan $47,236,105 Jeanne Shaheen Democrat New Hampshire $46,844,559 Mary L. Landrieu Democrat Louisiana $41,231,972 Source: Sunlight Foundation Influence Explorer , as of Oct. 30 *Amounts include all candidates’ expenditures plus outside spending.

While $140 million in dark money spent on "express" candidate advocacy was reported so far this year, another approximately $60 million used for generic issue advocacy is obfuscated and is not reported to the FEC. Jacob Fenton, a data expert at the Sunlight Foundation, said this latter type of advertising was epitomized by indirect messaging that says, “Did you know that your senator wasted billions of dollars? Call your senator to say he wasted billions of dollars!” Although dark money is only 5 percent of the more than $4 billion in election spending this record-breaking cycle, according to estimates by Sunlight, it’s a disproportionate chunk of the donations for swing races that will determine whether Republicans take control of the Senate. The top three sources of dark money are the U.S. Chamber of Commerce, Crossroads GPS and the NRA Institute for Legislative Action, which together have spent tens of millions supporting Republicans and attacking Democrats.

Since 2004, midterm spending has doubled – rising steadily except in 2008. Neda Djavaherian

Arcane rules govern different types of political action committees (PACs). Neda Djavaherian

“Outside spending continues to grow as a share of what is spent overall on elections,” said Viveca Novak of OpenSecrets. “Dark money looks like it may overtake super PAC spending as the category of outside groups most active in elections.” “There’s plenty of room for campaigns to be aware of what outside groups are doing, and that’s not illegal,” she said. “They can publicly announce it and often do let each other know. What they’re not supposed to do is plot strategy together.” Novak said there is not much hope for a constitutional amendment tackling unrestrained campaign financing that flopped around the Senate Judiciary Committee in January. One of the biggest proponents of looser regulations is Sen. Mitch McConnell, R-Ky., who could soon become majority leader. Of the $10 million in dark money spent in his race, 82 percent was to oppose Alison Lundergan Grimes, the Democratic challenger. In addition, advocates fear more sections of the landmark 2002 McCain-Feingold Act, which tightened the rules on campaign financing, could be further weakened by an unsympathetic Supreme Court. “To say [the outlook] is pretty dim is overstating the issue,” said Novak. “We are where we are for the time being.” There’s also an ongoing legal battle between Republican members of the Federal Election Commission and the commission’s own report about the potentially illegal use of dark money to influence politics. Citizens for Responsibility and Ethics in Washington, a watchdog group, originally filed the complaints to force the organizations in question to name their contributors. In the final days leading up to the Nov. 4 midterms, an estimated $20 million will be spent daily on federal campaigns alone. Despite advocates' efforts, U.S. elections will become only more expensive — and real campaign finance reform more elusive.