A slew of close Senate races across the country are threatening to tip in either party's direction between now and November 2, but if the best numbers available hold steady--and if they're accurate--Republicans will gain seven eight Senate seats in 2010.

That would mean 48 Republians and 52 Democrats 49 Republicans and 51 Democrats in the Senate.

The following is a curated roundup of the latest and best polling available in competitive Senate races, pulled largely from RealClearPolitics' vast compilation of surveys. Donkey and Elephant logos indicate which party currently controls the seat. 

The most recent polls with the largest sample sizes were included.

The list excludes Rasmussen surveys, which have favored Republican candidates by five to 10 percentage points consistently in races across the country. That, of course, does not mean Rasmussen is wrong. Pollsters and journalists have voiced skepticism of Rasmussen, however, and we can say with certainty that Rasmussen's numbers pull polling averages toward the GOP, for whatever reason. If you're interested in a list that excludes Rasmussen, this will be useful; if not, it won't be.

Two races are virtual ties: Illinois and Nevada. Leaders in those races (as expressed in this list) were determined by preponderance of advantage, recentness, and sample size of the last three major polls in the race. [UPDATE: Add Washington to the virtual-tie list.]

A handful of other races fall within certain polls' margin of error.

The list below does not show one race that will almost certainly see a Democratic seat turn red: South North Dakota, where Republican Gov. John Hoeven figures to easily replace retiring Democratic Sen. Byron Dorgan. [UPDATE: Democrats are poised to lose a seat in another noncompetitive race in Indiana, where retiring Sen. Evan Bayh (D) will likely be replaced by former Sen. Dan Coats (R).]

A total of 39 Senate elections will be held on Nov. 2. Of the 15 Democratic seats up for grabs, Democrats lead in eight of those races. Of the 24 Republican seats up for grabs, Republicans lead in all.

A total of 37 Senate elections will be held on Nov. 2. Of the 19 Democratic seats up for grabs, Democrats lead in 11 of those races. Of the 18 Republican seats up for grabs, Republicans lead in all.

The races below are either competitive now or were considered competitive at points in this election cycle:

DEMOCRATS LEAD IN:

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California: Sen. Barbara Boxer (D) leads Carly Fiorina (R)
  • SurveyUSA 9/30 - 10/3: Boxer +3
  • CNN/Time 9/24 - 28: Boxer +9
  • Field 9/14 - 21: Boxer +6

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Connecticut: Dick Blumenthal (D) leads Linda McMahon (R)
  • CNN/Time 10/1 - 5: Blumenthal +13
  • CT Capitol Report/McDowell Communications 10/3: Blumenthal +7
  • PPP 9/30 - 10/2: Blumenthal +12

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Delaware: Chris Coons (D) leads Christine O'Donnell (R)
  • Fairleigh Dickinson 9/27 - 10/3: Coons +17
  • CNN/Time 9/17 - 21: Coons +16
  • PPP 9/11 - 12: Coons +16

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Illinois: Alexi Giannoulias (D) leads Mark Kirk (R) in a virtual tie
  • Suffolk University 9/30 - 10/3: Kirk +1
  • CNN/Time 9/24 - 28: Giannoulias +1
  • Chicago Tribune 9/24 - 28: Giannoulias +2

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Washington: Sen. Patty Murray (D) leads Dino Rossi (R) in a virtual tie
  • AAF/Fabrizio McLaughlin (R) 9/26 - 27: Rossi +6
  • SurveyUSA 9/19 - 21: Murray +2
  • CNN/Time 9/10 - 14: Murray +9
  • Elway 9/9 - 12: Murray +9


REPUBLICANS LEAD IN:

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Alaska: Joe Miller (R) leads Sen. Lisa Murkowski (R) and Scott McAdams (D)
  • CNN/Time 9/24 - 28: Miller +2 over Murkowski, +16 over McAdams

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Arkansas: John Boozman (R) leads Sen. Blanche Lincoln (D)
  • Reuters/Ipsos 9/17 - 19: Boozman +14
  • Talk Business 9/16: Boozman +27
  • Mason-Dixon 9/12 - 14: Boozman +17

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Colorado: Ken Buck (R) leads Sen. Michael Bennet (D)
  • PPP 9/30 - 10/2: Bennet +1
  • Denver Post/SurveyUSA 9/28 - 30: Buck +5
  • McClatchy/Marist 9/26 - 28: Buck +8

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Florida: Marco Rubio (R) leads Charlie Crist (I) and Kendrick Meek (D)
  • Mason-Dixon 10/4 - 6: Rubio +15 over Crist, +21 over Meek
  • CNN/Time 9/24 - 28: Rubio +11 over Crist, +19 over Meek
  • Quinnipiac 9/23 - 26: Rubio +13 over Crist, +28 over Meek

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Kentucky: Rand Paul (R) leads Jack Conway (D)
  • SurveyUSA 9/21 - 23: Paul +2
  • Benenson (Dem internal) 9/24: Paul +3
  • PPP/Daily Kos 9/11 - 12: Paul +7

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Louisiana: Sen. David Vitter (R) leads Charlie Melancon (D)
  • Magellan Strategies (R) 9/19: Vitter +18
  • PPP 8/21 - 22: Vitter +10
  • WWL TV/Clarus 8/15 - 16: Vitter +12

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Missouri: Roy Blunt (R) leads Robin Carnahan (D)
  • CNN/Time 10/1 - 5: Blunt +13
  • Garin Hart Yang (Dem internal) 9/24: Blunt +1
  • PPP/Daily Kos 8/14 - 15: Blunt +7

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Nevada: Sharron Angle (R) leads Sen. Harry Reid (D) in a virtual tie
  • CNN/Time 10/1 - 5: Angle +2
  • Retail Association of Nevada (GOP internal) 9/21 - 23: Reid +5
  • LVRJ/Mason-Dixon 9/20 - 22: Tie

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New Hampshire: Kelly Ayotte (R) leads Paul Hodes (D)
  • American Research Group 10/3 - 5: Ayotte +5
  • WMUR/UNH 9/23 - 29: Ayotte +15
  • PPP 9/11 - 12: Ayotte +4

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North Carolina: Sen. Richard Burr (R) leads Elaine Marshall (D)
  • PPP 9/23 - 26: Burr +13
  • SurveyUSA 9/10 - 13: Burr +24
  • PPP 8/27 - 29: Burr +5

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Pennsylvania: Pat Toomey (R) leads Joe Sestak (D)
  • Morning Call 9/28 - 10/4: Toomey +7
  • McClatchy/Marist 9/26 - 28: Toomey +9
  • Suffolk University 9/24 - 27: Toomey +5

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West Virginia: John Raese (R) leads Joe Manchin (D)
  • PPP 9/18 - 19: Raese +3

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Wisconsin: Ron Johnson (R) leads Sen. Russ Feingold (D)
  • McClatchy/Marist 9/26 - 28: Johnson +7
  • CNN/Time 9/17 - 21: Johnson +6
  • PPP/Daily Kos 9/18 - 19: Johnson +11

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