2017 GovTrack Ideology US Senate Index

Ideology Analysis of Members of Congress

  The Govtrack ideology analysis assigns a liberal–conservative score to each Member of Congress based on his or her pattern of cosponsorship.  In a nutshell, Members of Congress who cosponsor similar sets of bills will get scores close together, while Members of Congress who sponsor different sets of bills will have scores far apart. Members of Congress with similar political views will tend to cosponsor the same set of bills, or bills by the same set of authors, and inversely Members of Congress with different political views will tend to cosponsor different bills.  You can find this analysis on the pages for current Members of Congress.

  The charts to the right plot the ideology score on the horizontal axis and the leadership score on the vertical axis. Look at the extremes. For instance, Sen. Jim Inhofe appears as the most extreme Republican in the Senate chart and he is widely regarded as one of the most conservative senators.

Overview

  The data that goes into this analysis is a list of who sponsored or cosponsored which bills. The process doesn’t look at the content of the bills or the party affiliation or anything else about the Members of Congress, but it is able to infer underlying behavioral patterns, some of which correspond to real-world concepts like left-right ideology.

  You’ll see in the charts on the right that the ideology analysis does a good job at separating the Democrats from the Republicans, and within each party the moderates from the extremes. If you wanted to know how your representatives stood in relation to their peers ideologically, this chart is a good place to start.

  We first began publishing this analysis in 2004, then calling it a political spectrum. A similar analysis by Professor Keith Poole using voting records rather than cosponsorship produces similar results: see voteview.com. (As far as we know, we were the first to apply this sort of analysis to cosponsorship behavior.)

2017 scorecard of US Senate & House

From this data.

US Senate

ideology	leadership	name	party	description	introduced_bills_115	cosponsored_bills_115
1.00	0.52	Inhofe	Republican	conservative Rep	2	39
0.92	0.51	Roberts	Republican	conservative Republican	3	27
0.91	0.18	Risch	Republican	lonely conservative Rep follower	2	32
0.90	0.51	Cruz	Republican	conservative Republican	8	30
0.89	0.63	Barrasso	Republican	conservative Republican	5	23
0.88	0.53	Enzi	Republican	conservative Republican	3	23
0.88	0.81	Cornyn	Republican	conservative Republican leader	6	36
0.87	0.56	Scott	Republican	conservative Republican	4	16
0.87	0.38	Fischer	Republican	conservative Republican	4	23
0.87	0.58	Lee	Republican	conservative Republican	9	29
0.85	0.45	Sessions	Republican	conservative Republican	0	1
0.85	0.47	Johnson	Republican	rank-and-file Republican	6	27
0.84	0.19	Lankford	Republican	moderate Rep follower	2	26
0.84	0.71	Thune	Republican	moderate Republican leader	5	23
0.83	0.42	Crapo	Republican	rank-and-file Republican	9	24
0.83	0.51	Boozman	Republican	rank-and-file Republican	1	32
0.83	0.13	Perdue	Republican	moderate Republican follower	1	30
0.82	0.20	Cotton	Republican	moderate Republican follower	1	25
0.82	0.55	Flake	Republican	rank-and-file Republican	7	25
0.81	0.24	Daines	Republican	rank-and-file Republican	10	34
0.81	1.00	McConnell	Republican	moderate Republican leader	10	17
0.80	0.61	Wicker	Republican	rank-and-file Republican	3	30
0.79	0.90	Hatch	Republican	moderate Republican leader	5	29
0.79	0.11	Rounds	Republican	moderate Republican follower	1	18
0.78	0.75	Blunt	Republican	moderate Republican leader	1	34
0.77	0.26	Gardner	Republican	rank-and-file Republican	8	25
0.76	0.80	Rubio	Republican	moderate Republican leader	27	41
0.76	0.54	Isakson	Republican	rank-and-file Republican	5	20
0.76	0.63	Moran	Republican	moderate Republican leader	6	25
0.76	0.32	Cassidy	Republican	rank-and-file Republican	8	17
0.75	0.51	Paul	Republican	rank-and-file Republican	4	15
0.75	0.43	McCain	Republican	rank-and-file Republican	5	24
0.74	0.86	Grassley	Republican	moderate Republican leader	10	24
0.74	0.37	Ernst	Republican	rank-and-file Republican	4	16
0.74	0.52	Hoeven	Republican	rank-and-file Republican	2	12
0.73	0.03	Tillis	Republican	moderate Republican follower	0	23
0.73	0.24	Sasse	Republican	rank-and-file Republican	2	14
0.73	0.30	Capito	Republican	rank-and-file Republican	3	22
0.72	0.52	Toomey	Republican	rank-and-file Republican	1	12
0.71	0.22	Sullivan	Republican	moderate Republican follower	5	28
0.71	0.18	Cochran	Republican	moderate Republican follower	0	16
0.70	0.59	Graham	Republican	centrist Republican	2	15
0.70	0.42	Burr	Republican	centrist Republican	2	8
0.69	0.22	Shelby	Republican	centrist Republican follower	1	11
0.67	0.55	Corker	Republican	centrist Republican	1	5
0.67	0.74	Alexander	Republican	centrist Republican leader	4	7
0.65	0.51	Heller	Republican	centrist Republican	26	20
0.62	0.76	Portman	Republican	centrist Republican leader	1	21
0.58	0.46	Manchin	Democrat	centrist Democrat	2	9
0.56	0.48	Murkowski	Republican	centrist Republican	13	19
0.56	0.00	Young	Republican	centrist Republican follower	1	15
0.53	0.00	Kennedy	Republican	centrist Republican follower	0	9
0.51	0.51	Heitkamp	Democrat	centrist Democrat	3	13
0.50	0.27	Donnelly	Democrat	centrist Democratic follower	1	10
0.47	0.00	Duckworth	Democrat	centrist Democratic follower	0	6
0.46	0.00	Harris	Democrat	centrist Democratic follower	0	12
0.46	0.00	Cortez Masto	Democrat	centrist Democratic follower	0	10
0.46	0.00	Hassan	Democrat	centrist Democratic follower	0	10
0.42	0.00	Van Hollen	Democrat	centrist Democratic follower	1	15
0.42	0.70	Nelson	Democrat	centrist Democrat	10	21
0.41	0.58	Tester	Democrat	centrist Democrat	2	23
0.40	0.70	Collins	Republican	centrist Republican leader	3	13
0.39	0.49	Warner	Democrat	rank-and-file Democrat	3	10
0.39	0.37	King	Independent	centrist Independent	3	17
0.38	0.33	McCaskill	Democrat	rank-and-file Democrat	2	12
0.36	0.29	Bennet	Democrat	rank-and-file Democrat	1	22
0.36	0.57	Carper	Democrat	rank-and-file Democrat	0	12
0.33	0.19	Peters	Democrat	moderate Democratic follower	1	18
0.30	0.51	Udall	Democrat	rank-and-file Democrat	4	14
0.30	0.27	Kaine	Democrat	moderate Democratic follower	1	16
0.26	0.74	Casey	Democrat	moderate Democratic leader	3	21
0.25	0.49	Cantwell	Democrat	rank-and-file Democrat	3	15
0.23	0.42	Booker	Democrat	rank-and-file Democrat	1	26
0.23	0.19	Heinrich	Democrat	moderate Democratic follower	1	21
0.22	0.74	Shaheen	Democrat	moderate Democratic leader	2	16
0.22	0.70	Klobuchar	Democrat	moderate Democratic leader	10	28
0.21	0.49	Coons	Democrat	rank-and-file Democrat	1	21
0.20	0.80	Wyden	Democrat	moderate Democratic leader	6	18
0.18	0.48	Stabenow	Democrat	rank-and-file Democrat	1	20
0.18	0.84	Cardin	Democrat	moderate Democratic leader	6	11
0.18	0.80	Feinstein	Democrat	moderate Democratic leader	6	16
0.17	0.70	Leahy	Democrat	moderate Democratic leader	0	15
0.16	0.43	Baldwin	Democrat	rank-and-file Democrat	5	22
0.14	0.30	Murphy	Democrat	rank-and-file Democrat	1	9
0.14	0.60	Murray	Democrat	rank-and-file Democrat	0	18
0.13	0.93	Menéndez	Democrat	moderate Democratic leader	2	14
0.13	0.38	Schatz	Democrat	rank-and-file Democrat	3	24
0.12	0.53	Schumer	Democrat	rank-and-file Democrat	3	6
0.12	0.49	Hirono	Democrat	rank-and-file Democrat	1	17
0.11	0.57	Reed	Democrat	rank-and-file Democrat	2	14
0.10	0.84	Brown	Democrat	progressive Democratic leader	3	27
0.09	0.64	Durbin	Democrat	progressive Democrat	0	23
0.08	0.61	Gillibrand	Democrat	progressive Democrat	2	20
0.08	0.48	Whitehouse	Democrat	progressive Democrat	2	20
0.08	0.51	Franken	Democrat	progressive Democrat	1	20
0.06	0.72	Blumenthal	Democrat	progressive Democratic leader	0	25
0.05	0.42	Sanders	Independent	left-leaning Independent	0	9
0.04	0.42	Markey	Democrat	progressive Democrat	3	17
0.03	0.39	Merkley	Democrat	progressive Democrat	0	23
0.00	0.59	Warren	Democrat	progressive Democrat	1	21

The 2017 House Ideology Index