SOUTH BEND  – Very close. That’s what the polls tell us about the race for the U.S. Senate in Indiana: Republican challenger Mike Braun vs. Sen. Joe Donnelly, the Democratic incumbent.
Very important. That’s how the race is viewed nationally, as the once seemingly impossible chance for Democrats to win control of the Senate as well as the House seems at least possible.
Very expensive. That’s obvious to anyone seeing myriad ads bought by the candidates and groups seeking to support or to destroy one or the other.
Polls showing a close race aren’t surprising. They just confirm what long was expected, that Donnelly, popular in the state even with many Republicans because of his moderate approach, would have a fighting chance to win, even though President Trump carried Indiana by 19 percentage points.
Here are results of two recent polls by major news organizations, both using professional pollsters and sampling likely voters.
An NBC News/Marist poll showed race at Donnelly, 49%; Braun, 4%.
A Fox News poll showed Braun, 45%; Donnelly, 43%.
OK, some readers looking at the poll sponsors will say: “Well, of course, Fox puts the Republican ahead and NBC has the Democrat winning.”
I don’t think that’s the case here. Each has professional pollsters concerned about their reputation for accuracy.
And the polls say about the same thing. That it’s close.
Any poll, no matter how professional the pollster, has what is called a margin for error. Without getting into a discussion of probability and statistics, that means that results from a sampling can’t be perfect. Taking the size of the sampling into consideration, pollsters estimate the possible variation statistically, plus or minus for any number, that could reasonably be expected.
Fox News, with a bigger sampling, listed a 3.5% margin for error. The total for either candidate could be off statistically by 3.5%. Thus, Donnelly actually could be ahead.
NBC, with a smaller sampling, listed a 5% margin for error. So, even with Donnelly up by 6 points, he actually could be trailing if both his and Braun’s totals were off by 5 points.
Real Clear Politics, which figures averages of all the recognized polls, found last week that they added up to Donnelly, 47.3; Braun, 43.5. That put the race in the “toss up” category.
Especially this far before the election, it’s too close to call. But the indication from the combination of polls that Donnelly could be at least a bit ahead is very good news for him.
It means that President Trump, in coming to Indiana to denounce Donnelly and appear with Braun, hasn’t mobilized all of those Hoosiers who voted for him in a landslide to slide the land from under Donnelly as well.
Actually, the poll numbers that could mean the most are those about support for the president. Since Trump seeks to make the race a referendum on himself, how Hoosiers view the president will be an important factor.
The Fox poll found Trump with a 54% approval rating in Indiana, much higher than in the rest of the nation. But on the question of whether support or opposition to Trump would serve as a reason for their Senate vote, it was a virtual tie; 33% of Hoosiers say support of Trump would be a reason, 31% say opposition to the president would be a reason.
The NBC poll showed Trump with a 48% favorability rating, also higher than nationally.
Always remember that any poll is only a snapshot for the time when taken, not a prediction of how things will be next week or on Election Day.
But it does seem certain that the Senate race will continue to be very close, very important, and very expensive. 

Colwell has covered Indiana politics for the South Bend Tribune for over five decades.