I'm not sure if every single one of these 50 races were the 50 closest in 2012, but at least 49 of them were. Several of these incumbents are already retiring if I'm not mistaken (for instance Utah's Jim Matheson), which should just make the house seats even more competitive/up for grabs. So here they are, the 50 closest House races of 2012:
1. NC-07: Mike McIntyre (D) 0.2% (margin of victory)
2. UT-04: Jim Matheson (D) 0.3%
3. IL-13: Rodney Davis (R) 0.3%
4. MI-01: Dan Benishek (R) 0.5%
5. FL-18: Patrick Murphy (D) 0.6%
6. AZ-02: Ron Barber (D) 0.8%
7. MA-06: Ron Tierney (D) 1.2%
8. IL-10: Brad Schneider (D) 1.2%
9. MN-06: Michele Bachmann (R) 1.2%
10. IN-02: Jackie Walorski (R) 1.4%
11. NY-27: Chris Collins (R) 1.6%
12. NE-02: Lee Terry (R) 1.6%
13. NY-21: Bill Owens (D) 1.9%
14. CO-06: Mike Coffman (R) 2.0%
15. CA-52: Scott Peters (D) 2.4%
16. CT-05: Elizabeth Esty (D) 2.6%
17. CA-07: Ami Bera (D) 3.4%
18. FL-10: Dan Webster (R) 3.4%
19. PA-12: Keith Rothfus (R) 3.4%
20. AZ-01: Ann Kirkpatrick (D) 3.6%
21. NH-01: Carol Shea-Porter (D) 3.8%
22. NY-23: Tom Reed (R) 3.8%
23. NY-18: Sean Maloney (D) 3.9%
24. KY-06: Andy Barr (R) 3.9%
25. OH-16: Jim Renacci (R) 4.0%
26. AZ-09: Kyrsten Sinema (D) 4.1%
27. TX-23: Pete Gallego (D) 4.7%
28. NH-02: Ann Kuster (D) 4.9%
29. NY-01: Tim Bishop (D) 5.0%
30. NY-24: Dan Maffei (D) 5.4%
31. CA-26: Julia Brownley (D) 5.4%
32. NY-11: Michael Grimm (R) 5.4%
33. CA-10: Jeff Denham (R) 5.4%
34. FL-02: Steve Southerland (R) 5.5%
35. NY-19: Chris Gibson (R) 5.7%
36. CA-36: Raul Ruiz (D) 5.8%
37. NC-09: Robert Pittenger (R) 6.1%
38. MI-11: Kerry Bentivolio (R) 6.4%
39. IL-17: Cheri Bustos (D) 6.6%
40. OH-06: Bill Johnson (R) 6.6%
41. FL-16: Vern Buchanan (R) 7.2%
42. GA-12: John Barrow (D) 7.4%
43. NV-03: Joe Heck (R) 7.5%
44. VA-02: Scott Rigell (R) 7.7%
45. WA-01: Suzan DelBene (D) 7.8%
46. NC-08: Richard Hudson (R) 7.8%
47. NV-04: Steven Horsford (D) 8.0%
48. WV-03: Nick Rahall (D) 8.0%
49. IA-04: Steve King (R) 8.1%
50. MN-02: John Kline (R) 8.2%
So that is 25 Democratic seats and 25 Republican seats. In addition we have the heavily Democratic-leaning California district 31 of course, which will be won back by Democrats this year after having been eliminated in the primaries in 2012.
Some states have far more close/competitive seats than most states, namely the following:
1. New York: 8 [of the top 50 seats] (almost 1/3 of its seats)
2. California: 5 seats
3. Florida: 4 seats
4. Arizona: 3 seats (almost half of seats)
5. North Carolina: 3 seats
6. Illinois: 3 seats
7. New Hampshire: 2 seats (100% of seats)
8. Nevada: 2 seats (50% of seats)
9. Minnesota: 2 seats (25% of seats)
10. Michigan: 2 seats
11. Ohio: 2 seats
Compare that to Texas, which only has one truely competitive seat for the time being.
In other words, house seats in New Hampshire, Nevada, Arizona, New York and Minnesota are particularily competitive. California, not so much, despite its non-partisan redistricting which it shares with Arizona (and possibly other states as well?).
Interesting that all of the most "vulnerable" seem to be white men.
Any of the 50 seats above which definitely won't be up for grabs this year?Source:
http://www.dailykos.com/story/2013/05/12/1208260/-The-closest-calls-in-the-2012-House-elections#