Throughout the midterm-election season, Ad Age has been issuing regular reports on TV and radio ad spending for key political races across the country. As the tallies grew, we scrambled to find the right words—e.g., "astonishing" and "unprecedented"—to describe what we were seeing. Now that we're at the end of the road, perhaps "obscene" is most apt.

According to the latest Ad Age Datacenter analysis of data from Kantar Media/CMAG, TV and radio campaign spending for just 10 of the most highly contested gubernatorial and U.S. Senate races totaled $967.5 million and counting (from January of last year through Nov. 6, 2018, including advance bookings). If you're reading this after Election Day, it's highly likely that number may have edged past the billion-dollar mark.

Who's to blame for the onslaught? That depends. In Missouri, TV/radio spending for the U.S. Senate seat up for grabs is pretty evenly split between Democrats ($50.5 million) and Republicans ($49.5 million). But in Florida, Republican TV/radio spending ($83.2 million) for the Senate seat in play far exceeds the Democratic outlay ($59.4 million).

Then again, when it comes to Florida's gubernatorial race, Democrats ($93.8 million) have handily outpaced Republicans ($77.2 million). Note: Our tallies include spending by the candidates and their parties, as well as groups, such as PACs, backing the candidates.

There are certain peculiarities to the 2018 midterms that have exacerbated the advertising arms race. For example, Florida's governor, Rick Scott, is term-limited and couldn't run again, so he mounted a wildly expensive race for a U.S. Senate seat instead.

The lack of an incumbent candidate always creates a vacuum that's handy for sucking up campaign-ad dollars, but things got extra nutty when Tallahassee Mayor Andrew Gillum defied all the odds (and polls) to win the Democratic primary. That means millions were wasted by assorted Democratic gubernatorial wannabes who crashed back to Earth when voters chose Gillum to take on Republican nominee Ron DeSantis. The Democratic machine then had to scramble to give the mayor of Florida's seventh-largest city wide exposure. (Tallahassee's population is just 189,907 in a state with 21 million people.)

In Illinois, meanwhile, the Democratic gubernatorial nominee, J.B. Pritzker, is a billionaire. By October, he'd blown through more cash—$161.5 million (spent on his campaign operations overall, including advertising)—than any other self-financed candidate in U.S. history, according to NPR.

Beyond ad dollars spent, there's another harrowing way to convey the degree to which Americans have been bombarded this midterm season. Kantar Media/CMAG's nationwide political spot count—the total number of TV ad placements for federal- and state-level races—is 4.5 million, Jan. 1-Oct. 30. For the equivalent period in 2016, the tally was 3.2 million—a 43 percent increase.

The temptation on Nov. 7 and thereafter is to think, well, at least it's over for now.

But of course it's not. A few weeks ago, the Federal Election Commission revealed that President Trump has already amassed a $100 million reelection war chest—the biggest ever for a sitting president. That's going to buy a lot of ads.

Ad Age Datacenter (Kevin Brown, Bradley Johnson and Catherine Wolf) partnered with Kantar Media/CMAG (Campaign Media Analysis Group) for this report.