TV advertising has gotten insanely expensive in the final weeks of the campaign.

TV pros have a term called "gross rating points" that is a measure of advertising units, and they say you need at least 1,000 gross rating points per week to get any saturation from an advertisement, and you really need 2,000 to do it right.

The cost of broadcast TV ads, in the final weeks of this hard-fought election season?

$1,000 per point.

So do the math: That's $1 million to air an ad, but really you ought to spend $2 million. Per week.

The cause: All the outside money flowing in for the four competitive House districts, all of which require TV ads in the expensive metro Twin Cities market. This has made Minnesota one of the most expensive states in the country this election season.

Those outside groups with anodyne names like the Congressional Leadership Fund and House Majority PAC don't get a discount like federal candidates receive, so they drive up rates.

This in turn has a big trickle-down effect on state level races, because state candidates also aren't eligible for a discount, so they pay market rates. Even digital platforms like the music service Pandora are sold out, a DFL operative told me last week. Unlike federal candidates, state level candidates are also burdened with spending caps because they are all taking a subsidy to help finance their campaigns.

That leads state candidates to be especially creative getting their name and message out. But TV is still the dominant way to reach the broadest audience of potential voters.

So even though Republican Jeff Johnson's closing ad in his bid for governor is receiving high marks from politicos, how often will it actually air? And without TV, can he catch his DFL opponent U.S. Rep. Tim Walz, who was leading Johnson in the most recent Minnesota Poll?

Puzzling the polls

The latest Star Tribune/MPR News Minnesota Poll offered fascinating results that gave both Republicans and Democrats reason to hope — and just as many reasons to be anxious.

Walz was up 45-39. Which means his support did not increase since our September poll. The problem for Johnson was that even though the race appears to have tightened, he still didn't manage to crack 40 percent.

But our poll of the attorney general's race created the most buzz, with Republican Doug Wardlow up over U.S. Rep. Keith Ellison by 7, with a whole lot of undecided voters, especially Democrats.

Democrats kicked into attack mode with a flurry of activity on social media warning fellow Democrats about Wardlow, calling him unfit for the office. It was reminiscent of a recent campaign in which Democrats desperately tried to warn their base about the Republican opposition. It was the 2016 presidential race.