US Senate Ideological Scores, 1st-119th Congress (VoteView DW-NOMINATE)

DW-NOMINATE ideology scores for all US senators from 1789 to 2025, showing voting patterns, party affiliation, and political polarization across 119 Congresses.
# congress
chamber
icpsr
state_icpsr
district_code
state_abbrev
party_code
occupancy
last_means
bioname
bioguide_id
born
died
nominate_dim1
nominate_dim2
nominate_log_likelihood
nominate_geo_mean_probability
nominate_number_of_votes
nominate_number_of_errors
conditional
nokken_poole_dim1
nokken_poole_dim2
1 1 President 99869 99 0 USA 5000 WASHINGTON, George
2 1 Senate 2936 1 0 CT 5000 0 3 ELLSWORTH, Oliver E000147 1745.0 1807.0 0.53 0.809 -24.37915 0.778 97 8 0.528 0.849
3 1 Senate 4998 1 0 CT 5000 0 3 JOHNSON, William Samuel J000182 1727.0 1819.0 0.991 0.137 -30.41227 0.69 82 16 0.997 0.075
4 1 Senate 507 11 0 DE 4000 0 3 BASSETT, Richard B000226 1745.0 1815.0 0.087 0.007 -38.18355 0.654 90 23 0.024 0.166
5 1 Senate 7762 11 0 DE 5000 0 3 READ, George R000091 1733.0 1798.0 0.282 -0.239 -34.31907 0.699 96 15 0.27 -0.206
6 1 Senate 3128 44 0 GA 4000 0 3 FEW, William F000100 1748.0 1828.0 -0.505 -0.433 -39.85431 0.626 85 27 -0.411 -0.515
7 1 Senate 3877 44 0 GA 4000 0 3 GUNN, James G000526 1753.0 1801.0 0.218 -0.884 -58.79459 0.492 83 31 -0.223 -0.975
8 1 Senate 1536 52 0 MD 5000 0 3 CARROLL, Charles (of Carrollton) C000185 1737.0 1832.0 0.234 -0.619 -55.73593 0.556 95 21 0.237 -0.603
9 1 Senate 4333 52 0 MD 5000 0 3 HENRY, John H000508 1750.0 1798.0 0.123 -0.573 -43.56209 0.638 97 29 0.106 -0.561
10 1 Senate 2307 3 0 MA 5000 0 3 DALTON, Tristram D000013 1738.0 1817.0 0.776 0.63 -28.51653 0.75 99 13 0.733 0.445
11 1 Senate 9028 3 0 MA 5000 0 3 STRONG, Caleb S001009 1745.0 1819.0 0.566 0.824 -21.53114 0.769 82 9 0.637 0.771
12 1 Senate 5449 4 0 NH 5000 0 3 LANGDON, John L000067 1741.0 1819.0 -0.37 0.107 -76.86324 0.396 83 30 0.308 -0.25
13 1 Senate 10272 4 0 NH 4000 0 3 WINGATE, Paine W000633 1739.0 1838.0 -0.037 0.999 -30.9409 0.729 98 19 -0.265 0.964
14 1 Senate 2576 12 0 NJ 5000 2 3 DICKINSON, Philemon D000324 1739.0 1809.0 0.609 -0.696 0.475 -0.076
15 1 Senate 2943 12 0 NJ 5000 0 3 ELMER, Jonathan E000155 1745.0 1817.0 0.408 0.171 -39.53793 0.631 86 23 0.411 0.22
16 1 Senate 7231 12 0 NJ 5000 1 3 PATERSON, William P000102 1745.0 1806.0 0.959 0.282 -20.33056 0.754 72 9 0.943 0.137
17 1 Senate 5270 13 0 NY 5000 0 3 KING, Rufus K000212 1755.0 1827.0 0.575 -0.302 -36.78581 0.682 96 16 0.939 -0.345
18 1 Senate 8282 13 0 NY 5000 0 3 SCHUYLER, Philip John S000154 1733.0 1804.0 0.949 -0.315 -25.31742 0.764 94 12 0.944 -0.329
19 1 Senate 4212 47 0 NC 5000 0 3 HAWKINS, Benjamin H000368 1754.0 1816.0 -0.046 -0.664 -33.14747 0.635 73 15 -0.313 -0.425
20 1 Senate 5012 47 0 NC 5000 0 3 JOHNSTON, Samuel J000198 1733.0 1816.0 -0.025 -0.527 -36.82361 0.62 77 20 -0.112 -0.43
21 1 Senate 5891 14 0 PA 4000 0 3 MACLAY, William M000031 1737.0 1804.0 -0.692 0.519 -23.63475 0.741 79 7 -0.698 0.541
22 1 Senate 6712 14 0 PA 5000 0 3 MORRIS, Robert M000985 1734.0 1806.0 0.7 -0.691 -40.20147 0.661 97 27 0.677 -0.598
23 1 Senate 3315 5 0 RI 5000 0 3 FOSTER, Theodore F000313 1752.0 1828.0 0.286 0.675 -25.599 0.657 61 10 0.297 0.955
24 1 Senate 8845 5 0 RI 4000 0 3 STANTON, Joseph, Jr. S000805 1739.0 1821.0 -0.091 0.736 -22.70883 0.689 61 11 -0.245 0.969
25 1 Senate 1346 48 0 SC 5000 0 3 BUTLER, Pierce B001186 1744.0 1822.0 -0.4 -0.912 -43.57708 0.632 95 31 -0.215 -0.977
26 1 Senate 4837 48 0 SC 5000 0 3 IZARD, Ralph I000053 1804.0 0.446 -0.587 -50.43903 0.601 99 29 0.375 -0.741
27 1 Senate 3771 40 0 VA 4000 1 3 GRAYSON, William G000403 1740.0 1790.0 -0.71 -0.294
28 1 Senate 5565 40 0 VA 4000 0 3 LEE, Richard Henry L000201 1732.0 1794.0 -0.384 -0.54 -28.12435 0.734 91 10 -0.446 -0.337
29 1 Senate 6594 40 0 VA 4000 3 3 MONROE, James M000858 1758.0 1831.0 -0.514 -0.762 -0.981 -0.192
30 1 Senate 9747 40 0 VA 5000 2 5 WALKER, John W000059 1744.0 1809.0 -0.552 -0.834 -31.37814 0.582 58 17 0.031 -1.0
31 2 President 99869 99 0 USA 5000 WASHINGTON, George
32 2 Senate 2936 1 0 CT 5000 0 3 ELLSWORTH, Oliver E000147 1745.0 1807.0 0.53 0.809 -15.45558 0.743 52 8 0.553 0.359
33 2 Senate 8457 1 0 CT 5000 2 3 SHERMAN, Roger S000349 1721.0 1793.0 0.589 0.307 -28.55038 0.578 52 19 0.33 0.2
34 2 Senate 507 11 0 DE 5000 0 3 BASSETT, Richard B000226 1745.0 1815.0 0.087 0.007 -17.85094 0.609 36 14 0.193 -0.104
35 2 Senate 7762 11 0 DE 5000 0 3 READ, George R000091 1733.0 1798.0 0.282 -0.239 -22.7154 0.646 52 10 0.293 -0.219
36 2 Senate 3128 44 0 GA 4000 0 3 FEW, William F000100 1748.0 1828.0 -0.505 -0.433 -18.96143 0.679 49 7 -0.614 -0.618
37 2 Senate 3877 44 0 GA 4000 0 3 GUNN, James G000526 1753.0 1801.0 0.218 -0.884 -16.1445 0.699 45 8 -0.322 -0.72
38 2 Senate 1118 51 0 KY 4000 0 3 BROWN, John B000929 1757.0 1837.0 -0.277 -0.548 -0.723 -0.305
39 2 Senate 2866 51 0 KY 4000 0 3 EDWARDS, John E000075 1748.0 1837.0 -0.725 -0.689 -0.192 -0.981
40 2 Senate 1536 52 0 MD 5000 1 3 CARROLL, Charles (of Carrollton) C000185 1737.0 1832.0 0.234 -0.619 -9.38567 0.771 36 3 0.434 -0.737
41 2 Senate 4333 52 0 MD 5000 0 3 HENRY, John H000508 1750.0 1798.0 0.123 -0.573 -12.26718 0.786 51 3 0.13 -0.673
42 2 Senate 7564 52 0 MD 5000 2 3 POTTS, Richard P000473 1753.0 1808.0 0.409 -0.816 -0.192 -0.981
43 2 Senate 1384 3 0 MA 5000 0 3 CABOT, George C000009 1752.0 1823.0 0.657 0.569 -13.70101 0.768 52 4 0.696 0.428
44 2 Senate 9028 3 0 MA 5000 0 3 STRONG, Caleb S001009 1745.0 1819.0 0.566 0.824 -13.35151 0.743 45 8 0.412 0.911
45 2 Senate 5449 4 0 NH 5000 0 3 LANGDON, John L000067 1741.0 1819.0 -0.37 0.107 -22.91596 0.62 48 12 0.144 0.095
46 2 Senate 10272 4 0 NH 4000 0 3 WINGATE, Paine W000633 1739.0 1838.0 -0.037 0.999 -7.18642 0.869 51 3 -0.243 0.97
47 2 Senate 2576 12 0 NJ 5000 0 3 DICKINSON, Philemon D000324 1739.0 1809.0 0.609 -0.696 -12.25672 0.783 50 2 0.615 -0.73
48 2 Senate 8150 12 0 NJ 5000 0 3 RUTHERFURD, John R000550 1760.0 1840.0 0.871 -0.252 -19.45933 0.643 44 11 0.902 0.302
49 2 Senate 1302 13 0 NY 4000 0 3 BURR, Aaron B001133 1756.0 1836.0 -0.887 -0.462 -21.58916 0.625 46 11 -0.902 -0.342
50 2 Senate 5270 13 0 NY 5000 0 3 KING, Rufus K000212 1755.0 1827.0 0.575 -0.302 -22.0203 0.62 46 13 0.669 -0.234
51 2 Senate 4212 47 0 NC 4000 0 3 HAWKINS, Benjamin H000368 1754.0 1816.0 -0.046 -0.664 -13.44937 0.768 51 5 -0.141 -0.838
52 2 Senate 5012 47 0 NC 5000 0 3 JOHNSTON, Samuel J000198 1733.0 1816.0 -0.025 -0.527 -18.24912 0.704 52 7 0.19 -0.774
53 2 Senate 6712 14 0 PA 5000 0 3 MORRIS, Robert M000985 1734.0 1806.0 0.7 -0.691 -11.36828 0.797 50 3 0.578 -0.772
54 2 Senate 3315 5 0 RI 5000 0 3 FOSTER, Theodore F000313 1752.0 1828.0 0.286 0.675 -13.86368 0.762 51 7 0.286 0.38
55 2 Senate 8845 5 0 RI 4000 0 3 STANTON, Joseph, Jr. S000805 1739.0 1821.0 -0.091 0.736 -22.43019 0.639 50 11 0.074 0.22
56 2 Senate 1346 48 0 SC 4000 0 3 BUTLER, Pierce B001186 1744.0 1822.0 -0.4 -0.912 -9.38197 0.791 40 5 -0.402 -0.916
57 2 Senate 4837 48 0 SC 5000 0 3 IZARD, Ralph I000053 1804.0 0.446 -0.587 -15.30178 0.741 51 6 0.439 -0.729
58 2 Senate 956 6 0 VT 4000 0 3 BRADLEY, Stephen Row B000745 1754.0 1830.0 0.09 -0.202 -35.6046 0.469 47 16 -0.498 0.08
59 2 Senate 7989 6 0 VT 4000 0 3 ROBINSON, Moses R000350 1741.0 1813.0 -0.732 0.649 -8.82423 0.835 49 5 -0.498 0.867
60 2 Senate 5565 40 0 VA 4000 1 3 LEE, Richard Henry L000201 1732.0 1794.0 -0.384 -0.54 -11.18776 0.705 32 4 -0.344 -0.596
61 2 Senate 6594 40 0 VA 4000 0 3 MONROE, James M000858 1758.0 1831.0 -0.514 -0.762 -13.20936 0.776 52 4 -0.467 -0.782
62 2 Senate 9215 40 0 VA 4000 2 3 TAYLOR, John T000086 1753.0 1824.0 -0.767 -0.6 -0.192 -0.981
63 3 President 99869 99 0 USA 5000 WASHINGTON, George
64 3 Senate 2936 1 0 CT 5000 0 3 ELLSWORTH, Oliver E000147 1745.0 1807.0 0.53 0.809 -11.15658 0.867 78 5 0.523 0.824
65 3 Senate 6574 1 0 CT 5000 2 3 MITCHELL, Stephen Mix M000828 1743.0 1835.0 0.696 -0.106 -6.14385 0.861 41 2 0.687 -0.083
66 3 Senate 8457 1 0 CT 5000 1 3 SHERMAN, Roger S000349 1721.0 1793.0 0.589 0.307
67 3 Senate 5494 11 0 DE 5000 2 3 LATIMER, Henry L000115 1752.0 1819.0 0.73 -0.043 0.632 0.289
68 3 Senate 9676 11 0 DE 5000 0 3 VINING, John V000104 1758.0 1802.0 0.433 -0.264 -11.0674 0.821 56 6 0.452 -0.249
69 3 Senate 3877 44 0 GA 4000 0 3 GUNN, James G000526 1753.0 1801.0 0.218 -0.884 -21.72006 0.669 54 12 0.017 -0.673
70 3 Senate 4854 44 0 GA 4000 0 3 JACKSON, James J000017 1757.0 1806.0 -0.32 -0.181 -23.8025 0.722 73 13 -0.397 -0.2
71 3 Senate 1118 51 0 KY 4000 0 3 BROWN, John B000929 1757.0 1837.0 -0.277 -0.548 -16.42979 0.788 69 7 -0.4 -0.32
72 3 Senate 2866 51 0 KY 4000 0 3 EDWARDS, John E000075 1748.0 1837.0 -0.725 -0.689 -10.06694 0.814 49 6 -0.784 -0.62
73 3 Senate 4333 52 0 MD 5000 0 3 HENRY, John H000508 1750.0 1798.0 0.123 -0.573 -18.30761 0.61 37 8 0.32 -0.594
74 3 Senate 7564 52 0 MD 5000 0 3 POTTS, Richard P000473 1753.0 1808.0 0.409 -0.816 -22.09264 0.723 68 11 0.453 -0.891
75 3 Senate 1384 3 0 MA 5000 0 3 CABOT, George C000009 1752.0 1823.0 0.657 0.569 -14.4034 0.829 77 6 0.652 0.392
76 3 Senate 9028 3 0 MA 5000 0 3 STRONG, Caleb S001009 1745.0 1819.0 0.566 0.824 -9.55208 0.838 54 6 0.807 0.537
77 3 Senate 5449 4 0 NH 4000 0 3 LANGDON, John L000067 1741.0 1819.0 -0.37 0.107 -18.01202 0.725 56 7 -0.277 0.365
78 3 Senate 5713 4 0 NH 5000 0 3 LIVERMORE, Samuel L000364 1732.0 1803.0 0.35 0.731 -23.4757 0.731 75 13 0.216 0.923
79 3 Senate 3361 12 0 NJ 5000 0 3 FRELINGHUYSEN, Frederick F000368 1753.0 1804.0 0.958 -0.283 -20.70524 0.727 65 14 0.927 -0.135
80 3 Senate 8150 12 0 NJ 5000 0 3 RUTHERFURD, John R000550 1760.0 1840.0 0.871 -0.252 -20.5583 0.693 56 13 0.853 -0.522
81 3 Senate 1302 13 0 NY 4000 0 3 BURR, Aaron B001133 1756.0 1836.0 -0.887 -0.462 -9.3311 0.839 53 5 -0.621 -0.572
82 3 Senate 5270 13 0 NY 5000 0 3 KING, Rufus K000212 1755.0 1827.0 0.575 -0.302 -18.32204 0.767 69 7 0.487 -0.126
83 3 Senate 4212 47 0 NC 4000 0 3 HAWKINS, Benjamin H000368 1754.0 1816.0 -0.046 -0.664 -31.12315 0.653 73 20 0.039 -0.804
84 3 Senate 6012 47 0 NC 4000 0 3 MARTIN, Alexander M000166 1740.0 1807.0 -0.146 -0.844 -19.4632 0.774 76 9 -0.253 -0.958
85 3 Senate 3437 14 0 PA 4000 1 3 GALLATIN, Albert G000020 1761.0 1849.0 -0.112 -0.105 0.347 -0.938
86 3 Senate 6712 14 0 PA 5000 0 3 MORRIS, Robert M000985 1734.0 1806.0 0.7 -0.691 -16.84202 0.783 69 6 0.753 -0.349
87 3 Senate 8070 14 0 PA 5000 2 3 ROSS, James R000448 1762.0 1847.0 0.85 -0.526 -43.47373 0.372 44 26 0.935 -0.354
88 3 Senate 951 5 0 RI 5000 0 3 BRADFORD, William B000739 1729.0 1808.0 0.554 0.598 -12.98814 0.847 78 6 0.588 0.73
89 3 Senate 3315 5 0 RI 5000 0 3 FOSTER, Theodore F000313 1752.0 1828.0 0.286 0.675 -17.399 0.793 75 9 0.321 0.509
90 3 Senate 1346 48 0 SC 4000 0 3 BUTLER, Pierce B001186 1744.0 1822.0 -0.4 -0.912 -6.58241 0.824 34 3 -0.235 -0.972
91 3 Senate 4837 48 0 SC 5000 0 3 IZARD, Ralph I000053 1804.0 0.446 -0.587 -16.75476 0.782 68 4 0.526 -0.468
92 3 Senate 956 6 0 VT 4000 0 3 BRADLEY, Stephen Row B000745 1754.0 1830.0 0.09 -0.202 -19.92373 0.66 48 13 -0.276 0.172
93 3 Senate 7989 6 0 VT 4000 0 3 ROBINSON, Moses R000350 1741.0 1813.0 -0.732 0.649 -10.76146 0.833 59 4 -0.66 0.259
94 3 Senate 6594 40 0 VA 4000 1 3 MONROE, James M000858 1758.0 1831.0 -0.514 -0.762 -4.62478 0.9 44 3 -0.64 -0.768
95 3 Senate 9215 40 0 VA 4000 1 3 TAYLOR, John T000086 1753.0 1824.0 -0.767 -0.6 -2.06706 0.943 35 1 -0.564 -0.826
96 3 Senate 9238 40 0 VA 4000 2 3 TAZEWELL, Henry T000107 1753.0 1799.0 -0.666 -0.383 0.351 -0.936
97 4 President 99869 99 0 USA 1 WASHINGTON, George
98 4 Senate 2936 1 0 CT 1 1 3 ELLSWORTH, Oliver E000147 1745.0 1807.0 0.53 0.809 0.704 -0.047
99 4 Senate 4433 1 0 CT 1 2 3 HILLHOUSE, James H000618 1754.0 1832.0 0.691 -0.249 0.59 -0.438
100 4 Senate 9452 1 0 CT 1 2 3 TRACY, Uriah T000348 1755.0 1807.0 0.727 0.328 0.468 0.884

US Senate Ideological Scores, 1st-119th Congress (VoteView DW-NOMINATE) — Analysis

Senate polarization is at a 170-year high: the ideological gap between parties (0.92) has nearly doubled since its mid-century low (0.47 in 1941)

Zero overlap remains between the parties — no Democrat votes more conservatively than any Republican for the first time in recorded history

Cross-Party Ideological Overlap by Era
Most Ideologically Extreme Senators (119th Congress)
Ideological Gap Between Parties
Party Ideology Scores Over Time

Key Findings

  • The ideological gap between Senate Democrats and Republicans nearly doubled from 0.47 (77th Congress, 1941) to 0.92 (119th Congress, 2025)
  • Republican rightward shift drove most of the recent divergence: the GOP mean moved from +0.25 in 1941 to +0.56 in 2025, while Democrats moved from -0.22 to -0.37
  • Cross-party ideological overlap has collapsed from 22% of senators in 1915-1934 to 0% in 2015-2026
  • Elizabeth Warren (D-MA) is the most liberal senator (-0.745) and Tommy Tuberville (R-AL) the most conservative (+0.936) in the current Congress
  • The mid-20th century (1935-1975) stands out as the era of lowest polarization, largely due to conservative Southern Democrats

Senate Age Trends Over Two Centuries

  • The average age of U.S. Senators has risen substantially over time, from a mean of 46.7 years in 1789 to 64.2 years in ~2025.
  • The youngest Senate on record (by mean age) was in ~1793 at 44.1 years, while the oldest is the current 119th Congress at 64.2 years.
  • Mean and median age track closely throughout history, with the current median at 65.0 years — indicating a fairly symmetric age distribution.
  • A notable acceleration in average age began around 1980, with mean age climbing from roughly 53 to over 64 years by the current Congress.
Mean and Median Age of U.S. Senators by Congress (1789–Present)

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