Senate Minority Leader Mitch McConnell of Kentucky and Democratic opponent Alison Lundergan Grimes, shown in this Oct. 13 file-pool photo, are in a tight race despite heavy spending. (Pablo Alcala/AP)

For an election that few people are paying attention to, it’s turning into a pretty exciting one. There are at least 11 Senate races in which the outcome is far from certain, with about a week left before voters go to the polls Nov. 4.

That’s an unusually high amount of uncertainty this late in an election. Typically, the playing field winnows with every passing week as party committees (and candidates) are forced to make fish-or-cut-bait decisions on races that just don’t look winnable. The Cook Political Report, a nonpartisan handicapping service, had just seven “tossup” races in 2010 and six in 2008. Today, it rates 10 races as tossups.

The only race that has fallen by the wayside this cycle is the Michigan open-seat contest, in which national Republicans pulled their advertising this month in the face of poll numbers that suggested Rep. Gary Peters (D) was likely to beat former secretary of state Terri Lynn Land (R).

But aside from Michigan, there haven’t been any races that have collapsed for either side, and, in fact, South Dakota, Kansas and Georgia — Republican-held seats — have come on the map, in varying degrees, over the past six weeks or so. The Real Clear Politics polling average shows eight races within a five-point margin, a remarkable level of competitiveness this late in an election season.

While that is welcome news for political junkies — the more, the merrier! — it does put the national party committees in a tough spot. Money is finite, and that means that making decisions about how it should be spent is of critical importance in the waning days of any race. Because there are so many competitive Senate contests, the where, how and when of cash distribution in the final days matters even more. And the closeness of so many races means that second-guessing of whichever side comes up short is inevitable.

Independent candidate Greg Orman, left, and Sen. Pat Roberts, R-Kan., square off during their debate Oct. 15 in Wichita, Kan. Polls show the race as being close, but Roberts is still unpopular. (Fernando Salazar/AP)

Below are our rankings of the 13 most competitive Senate races in the country. The race ranked No. 1 is the most likely to flip parties.

13. Kentucky (Republican-controlled): Two things are true about this race. 1) Sen. Mitch McConnell has not been able to pull away from Democrat Alison Lundergan Grimes despite massive spending. 2) This is Kentucky in a midterm election that looks bad for Democrats nationally. McConnell is a slight favorite, but both sides are engaged in this race and are spending, which suggests that the outcome isn’t quite decided.

12. New Hampshire (Democratic-controlled): Former Massachusetts senator Scott Brown (R) and Sen. Jeanne Shaheen (D) debated twice in the past week, but there were no big momentum-shifting moments. Polls show Shaheen is popular and has a small lead, within the margin of error. This race is making Democrats more nervous than it was a couple months ago.

11. North Carolina (D): Republican Thom Tillis has faced a whopping $26 million in negative ads — more than any Senate candidate and about twice as much as Sen. Kay Hagan (D) (though that excludes plenty of ads from conservative-aligned nonprofit groups that were run against Hagan over the summer). This race is tightening, and Hagan’s narrow lead is shrinking.

10. Georgia (R): Democrat Michelle Nunn clearly has the momentum — a new CNN poll Friday had her up three points — in the wake of Republican David Perdue’s controversial comments on outsourcing, but it’s likely that we’re headed for a Jan. 6 runoff. If anyone wins Nov. 4, however, it seems as if it will be Nunn.

9. Iowa (D): Recent polling shows state Sen. Joni Ernst (R) and Rep. Bruce Braley (D) tied or within the margin of error of each other; an NBC-Marist survey released Sunday gave Ernst a three-point edge. This looks as if it will be the closest race in the country.

8. Kansas (R): Independent Greg Orman was at 45 percent to 44 percent for Sen. Pat Roberts (R) in an NBC-Marist poll released Sunday. Republicans like the direction in which the race is moving — Orman was up 10 the last time NBC polled the race — but Roberts remains deeply unpopular.

7. Colorado (D): All of the movement here is in the direction of Rep. Cory Gardner (R). Gardner has led Sen. Mark Udall (D) in the past 10 polls, and, according to the Real Clear Politics polling average, he is up by more than three points.

6. Alaska (D): Republican Dan Sullivan has led Sen. Mark Begich (D) by two to six points in every public poll out this fall. Democrats are keeping the faith because of their well-oiled ground game and early-vote operation. If the election ends up being close, we may not know the outcome until well after Nov. 4 because of how long it will take to count absentee ballots.

5. Louisiana (D): This race looks headed to a Dec. 6 runoff, with neither Sen. Mary Landrieu (D) nor Rep. Bill Cassidy (R) likely to get to 50 percent on Nov. 4. A runoff electorate in a conservative state such as Louisiana should favor the Republican.

4. Arkansas (D): Rep. Tom Cotton (R) has led by two to eight points in the past six polls here, and Democratic Sen. Mark Pryor’s days are looking increasingly numbered. Cotton overcame early rumblings that he wasn’t a great candidate to run a solid campaign.

3. South Dakota (D): Former governor Mike Rounds (R) hasn’t been a good candidate. But new NBC-Marist numbers show him comfortably ahead of Democrat Rick Weiland, with former GOP Sen. Larry Pressler, who is running as an independent, lagging in third.

2. West Virginia (D): Rep. Shelley Moore Capito (R) is quietly running one of the best campaigns in the country. Capito has made zero mistakes, which has left no opening for Secretary of State Natalie Tennant (D). This is pretty much over.

1. Montana (D): Sen.-elect Steve Daines (R).