While the 2016 presidential election might have scrapped just about every norm of American elections, one standard rule remains useful in 2018: follow the money.

A problem one might run into in this pursuit, however, is that a growing amount of money spent on elections in the US is untraceable, "dark money." And regarding the current election cycle, this is as true as it has ever been.

Nearly $1 billion has been spent (so far) on political advertisements during this election cycle. Over two million ads for Congressional and Gubernatorial races have already aired, according to a report released on September 20 by the Wesleyan Media Project and the Center for Respective Politics.

Compared to the 2014 election cycle, 2018 has seen a 70 percent increase in TV ads.

"Dark money" spending, a term for political spending conducted by 501(c)(4) nonprofit organizations (and certain super PACs) that are not required to disclose who their donors are to the Federal Election Commission (FEC), is at an all-time high this election cycle. Since Labor Day alone, 280,000 ads have been aired on TV, and nearly half (48 percent) were run by groups that do not disclose their donors.

Outside spending is not contained within any particular part of the country. Ads run by outside groups are reaching people all across the United States. More than half of the ads ran in Missouri and West Virginia were sponsored by outside groups, and "more than one in every three ads in Indiana, Arizona, Nevada, and North Dakota have been paid for by outside groups," according to the report.

Dark money is partisan in the Senate

Spending on Senate races has been dominated by outside groups. (And highly partisan outside groups, specifically).

Majority Forward, a 501(c)(4) nonprofit organization tied to the Democratic leadership in Congress, has been pouring huge sums of money into Democratic Senate races during September.

According to Anna Massaglio of Open Secrets News, the group has aired "more than 13,410 spots in six Senate races at an estimated cost of more than $3 million in the last two weeks alone."

Since Labor Day, over 90 percent of money spent backing Senate hopefuls on the Democratic side has come from non-disclosing sources.

On the Republican side, most spending during this cycle has not come from outside groups.

(Although there are some notable exceptions, such as money spent by the Koch network.)

The Senate Leadership Fund, a super PAC required to disclose its donors, accounts for most of the money (nearly $27 million) spent backing GOP candidates for the Senate in 2018. In the House, however, outside groups have played a larger role for Republicans. Although the Congressional Leadership Fund (CLF), another super PAC that has spent more than half of all the money backing Republicans in House races this cycle, is donor-disclosing, the group has received funding from many "dark money" sources -- such as the politically active 501(c)(4) known as the American Action Network.

The effect 'dark money' will have in November

Erika Franklin Fowler, the co-director of the Wesleyan Media Project, has expressed concern for the effect this level of outside spending has had on the American people leading up to November. “Dollars spent on TV stretch further this year," she said, "and the consequence is that Americans are seeing many more ads than in 2014 at this same point.”

Fowler also pointed out that while the total amount of spending by outside groups is high, "it is striking that across all of the races for Congress and governor this cycle, the ad totals are essentially even between the two parties.”

In an America that has arguably never been so politically polarized, the massive amount of outside spending conducted by both Republican and Democratic groups this election cycle will surely make the midterms in November even more hectic (if that is even possible at this point).