The Senators you want to resign

When the Senate is pretty evenly divided - as it is now (Pence has already had to cast 6 tie-breaking votes) every single seat counts. And because sometimes a Senator who resigns (or dies) can be replaced with someone from another party, having a sitting Senator - like let's say Sen. Bob Menendez (D-NJ) who's governor is a Republican - leave office can have a large impact on the Senate and legislation.

But not all resignations are equal. Having a Democrat from a blue state with a Democratic governor resign is not the same as having a Republican from a swing state with a Democratic governor resign. So if you're rooting for resignations (not deaths, that's unseemly) who should you root for? Below I have ranked the 100 Senators by how much it would help Democrats for them to resign. For Republicans, just reverse it.

I grouped them by their legal process and governor status but these may not always work. For example, having Murkowski, who sometimes votes with Democrats, resign might be far worse than having Cruz, whose seat is marginally competitive, resign.

The names in bold color are the 10 oldest Senators, colored by party.

Where I put "Election in 2018" I mean on November 6, 2018 and before 2018 means anytime before that (which will likely be in 2018).

Ties within groups are ranked by how well Hillary /Trump did in that state in the 2016 presidential race as a way of noting how "flippable" those seats are in the next election (special or general). Ties between Senators from the same state are broken by age with a younger Senator resigning being more desirable if they're in the other party (older if they're in yours), since the older Senator is more likely to retire or resign later.

A Menendez retirement in 2017 would be very bad for Democrats.

Update: Updated on January 6, 2018 because of election of Jones, a change of party for the New Jersey Governor and the Franken resignation.

D Governor replaces R Senator, election in 2018

1. Gardner (R-CO)
2. Toomey (R-PA)
3. Daines (R-MT)

D Governor replaces R Senator, special before 2018

4. Kennedy (R-LA)
5. Cassidy (R-LA)

D Governor replaces R Senator with another R (by law), special in 2018

6. Tillis (R-NC)
7. Burr (R-NC)

No replacement of R Senator, special before 2018

8. Hoeven (R-ND)
9. Lankford (R-OK)
10. Inhofe (R-OK)

I Governor replaces R Senator, special before 2018

11. Sullivan (R-AK)
12. Murkowski (R-AK)

R Governor replaces R Senator, special before 2018

13. Johnson (R-WI)
14. Cruz (R-TX)
15. Cornyn (R-TX)
16. Shelby (R-AL)

R Governor replaces R Senator, special in 2018

17. Collins (R-ME)
18. Rubio (R-FL)
19. McCain (R-AZ)
20. Isakson (R-GA)
21. Perdue (R-GA)
22. Portman (R-OH)
23, Ernst (R-IA)
24. Grassley (R-IA)
25. Scott (R-SC)
26. Graham (R-SC)
27. Cochran (R-MS)
28. Wicker (R-MS)
29. Lee (R-UT)
30. Young (R-IN)
31. Moran (R-KS)
32. Roberts (R-KS)
33. Sasse (R-NE)
34. Alexander (R-TN)
35. Cotton (R-AR)
36. Boozeman (R-AR)
37. Thune (R-SD)
38. Rounds (R-SD)
39. Paul (R-KY)
40. McConnell (R-KY)
41. Crapo (R-ID)
42. Risch (R-ID)
43. Capito (R-WV)
44. Enzi (R-WY)

R Governor replaces R Senator, term ends in 2018 

45. Heller (R-NV)
46. Flake (R-AZ)
47. Hatch (R-UT)
48. Blunt (R-MO)
49. Fischer (R-NE)
50. Corker (R-TN)
51. Barasso (R-WY)

D Governor replaces D Senator, term ends in 2018 

52. Hirono (D-HI)*
53. Feinstein (D-CA)
54. Gillibrand (D-NY)
55. Menendez (D-NJ)
56. Booker (D-NJ)
57. Carper (D-DE)
58. Kaine (D-VA)
59. Klobucher (D-MN)
60. Smith (D-MN)
61. Casey (D-PA)
62. Tester (D-MT)

D Governor replaces D Senator, special in 2018

63. Schatz (D-HI)*
64. Harris (D-CA)
65. Schumer (D-NY)
66. Coons (D-DE)
67. Warner (D-VA)
68. Bennet (D-CO)

D Governor replaces D Senator, special before 2018

69. Markey (D-MA)
70. Warren (D-MA)
71. Murray (D-WA)
72. Cantwell (D-WA)
73. Murphy (D-CT),

No replacement of D Senator, special before 2018

74. Blumenthal (D-CT)
75. Reed (D-RI)
76. Whitehouse (D-RI)
77. Wyden (D-OR)
78. Merkley (D-OR)
79. Heitkamp (D-ND)

R Governor replaces D Senator, special before 2018

80. Leahy (D-VT)
81. Sanders (I-VT)
82. Baldwin (D-WI)

R Governor replaces D Senator

83. Cardin (D-MD)
84. Van Hollen (D-MD)
85. Durbin (D-IL)
86. Duckworth (D-IL)
87. Udall (D-NM)
88. Heinrich (D-NM)
89. King (I-ME)
90. Masto (D-NV)
91. Shaheen (D-NH)
92. Hassan (D-NH)
93. Stabenow (D-MI)
94. Peters (D-MI)
95. Nelson (D-FL)
96. Brown (D-OH)
97. McCaskeill (D-MO)
98. Donnelly (D-IN)
99. Jones (D-AL)
100. Manchin (D-WV)

+ Governor is an Independent, has been a Republican and ran with the Democratic nominee
*Party leaders pick the possible replacements and governor selects from them
++if vacancy occurs before March 2018, otherwise seat empty till Nov 2018