The Vote Ledger
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Data through Sep 17, 2026Compare members
The Vote Ledger
MM

Michael Joseph (Mike) Mansfield

Senator from Montana
SENATEDEMOCRAT1943–1977ID M000113
Compare
LegislationHEADLINE
89%with Dems
of 3,320 votes
Nominations
—with Dems
of 0 · confirmations only
All contested
89%with Dems
of 3,320 · both combined
Steepest move
−9 pts
1965 → 1967
still a Democrat

Career arc

Legislation leads. Each point is one Congress: how often they sided with the Democratic majority on contested bills, resolutions and amendments.

100%75%50%25%0%sides with Democrats ↑sides with Republicans ↓194319491955196119671973
1975–7694th Congress
Sat as a Democrat
87.1%with Democrats
of 488 contested votes
Votes for this Congress are open below
Steepest move: 1965 → 1967, −9 pts — while still a Democrat.
Sat as a DemocratSat as a RepublicanVotes available below

Votes

9 of these 9 roll calls have no description. About 25% of roll calls since 1989 are blank in the source too. Some also lack a bill number.

DateBillVoteTypeCastSided with
Sep 17, 1976H.R. 14232No description in the source recordLEGISLATIONNAYNEITHER · NOT SCORED
Sep 17, 1976H.R. 8800No description in the source recordLEGISLATIONYEADEM MAJORITY
Sep 16, 1976H.R. 10612No description in the source recordLEGISLATIONYEABOTH · NOT SCORED
Full textNo description in the source record. What survives: the date, the bill number (H.R. 10612), how they voted and which side that matched.Party majoritiesDemocrats Yea · Republicans YeaCounts toward scoreNo — both party majorities voted Yea.
Where this lands
YEAVoted with both majorities — not scored
Sep 16, 1976H.R. 10612No description in the source recordLEGISLATIONYEABOTH · NOT SCORED
Sep 16, 1976H.R. 1386No description in the source recordLEGISLATIONYEANEITHER · NOT SCORED
Sep 16, 1976noneNo description in the source recordLEGISLATIONYEABOTH · NOT SCORED
Sep 15, 1976H.R. 14846No description in the source recordLEGISLATIONYEABOTH · NOT SCORED
Sep 15, 1976H.R. 14846No description in the source recordLEGISLATIONNAYNEITHER · NOT SCORED
Sep 15, 1976S.Con.Res. 139No description in the source recordLEGISLATIONYEADEM MAJORITY
9 most recent roll calls shown · 488 contested votes scored in the 94th CongressAll votes this Congress →

By policy area

career · legislation
Government Operations and Politics84.4% · 135 votes
Economics and Public Finance82.3% · 113 votes
Armed Forces and National Security100% · 60 votes
Taxation94.9% · 59 votes
Energy85.2% · 54 votes
Law92.5% · 53 votes
Congress71.4% · 42 votes
International Affairs87.5% · 32 votes
Public Lands and Natural Resources84% · 25 votes
Commerce95.8% · 24 votes
Depletion allowances39.1% · 23 votes
Agriculture and Food95% · 20 votes
Education78.9% · 19 votes
Foreign Trade and International Finance94.7% · 19 votes
Power resources100% · 17 votes
Independent regulatory commissions100% · 16 votes
Transportation and Public Works87.5% · 16 votes
Congressional-Presidential relations90.9% · 11 votes
Health90.9% · 11 votes
Labor and Employment90% · 10 votes
Political participation70% · 10 votes
Social Welfare100% · 10 votes
Too few contested votes to score
Automobile insurance— · 8 votes
Environmental Protection— · 8 votes
Public works— · 8 votes
Finance and Financial Sector— · 7 votes
Crime and Law Enforcement— · 6 votes
Intergovernmental relations— · 6 votes
Mortgages— · 5 votes
Science, Technology, Communications— · 5 votes
Credit— · 4 votes
Housing and Community Development— · 4 votes
Petroleum industry— · 4 votes
Day care— · 3 votes
Mines and mineral resources— · 3 votes
Range management— · 3 votes
Territories (U.S.)— · 3 votes
District of Columbia— · 2 votes
Government corporations— · 2 votes
Government publications— · 2 votes
Motor vehicles— · 2 votes
Private Legislation— · 2 votes
Sports and Recreation— · 2 votes
Commemorations— · 1 vote
Congressional oversight— · 1 vote
Constitutional amendments— · 1 vote
Dairy industry— · 1 vote
Disaster relief— · 1 vote
Economic stabilization— · 1 vote
Federal advisory bodies— · 1 vote
Heating— · 1 vote
Intergovernmental fiscal relations— · 1 vote
Lobbying— · 1 vote
Monuments and memorials— · 1 vote
Ships and shipping— · 1 vote
Vietnamese Conflict— · 1 vote

They also voted in 27 areas where the parties never split, so there is nothing to score — never on a contested question: Animals, Arts, Culture, Religion, Awards, medals, prizes, Child welfare, Congressional-executive relations, Conservation of natural resources, Emergency Management, Executive reorganization, Explosives, Gold, Immigration, Interest, Lakes, Land use, Lead poisoning, Livestock, Medical supplies, Mobile homes, Native Americans, Postal rates and revenues, Postal service, Reclamation of land, Refugees, Revenue sharing, Right of privacy, Rivers, Strategic materials.

Blue is the share of votes siding with the Democratic majority; the tick marks 50%.

Service record

17 Congresses
78th · 194383rd · 195394th · 1975
Democrat · House · MT78th–82nd
Democrat · Senate · MT83rd–94th
Term datesexact
Members · Montana
MM

Michael Joseph (Mike) Mansfield

Senator from Montana
SENATED1943–197717 CONGRESSES
Compare
LegislationHEADLINE
88.6%with Democrats
of 3,320 votes · 11.4% with Republicans
Nominations—of 0 votes
All contested89%of 3,320 · combined
Steepest move−9 pts1965→67, as a Democrat

Career arc

10050019431975
1975–76 · 94th · Democrat · of 488 votes87.1%

Legislation leads. Tap a point to read that Congress.

Votes

About 25% of roll calls since 1989 are blank too. These rows carry a date, a bill number where one exists, how they voted and which side that matched.
Democratic majorityYea
Republican majorityYea
Counts toward scoreNo
Open roll call
Latest 6 shown · 488 contested votes scored in the 94th

By policy area

career
Government Operations and Politics84.4% · 135
Economics and Public Finance82.3% · 113
Armed Forces and National Security100% · 60
Taxation94.9% · 59
Energy85.2% · 54
Law92.5% · 53
Congress71.4% · 42
International Affairs87.5% · 32
Public Lands and Natural Resources84% · 25
Commerce95.8% · 24
Depletion allowances39.1% · 23
Agriculture and Food95% · 20
Education78.9% · 19
Foreign Trade and International Finance94.7% · 19
Power resources100% · 17
Independent regulatory commissions100% · 16
Transportation and Public Works87.5% · 16
Congressional-Presidential relations90.9% · 11
Health90.9% · 11
Labor and Employment90% · 10
Political participation70% · 10
Social Welfare100% · 10
Automobile insurance— · 8
Environmental Protection— · 8
Public works— · 8
Finance and Financial Sector— · 7
Crime and Law Enforcement— · 6
Intergovernmental relations— · 6
Mortgages— · 5
Science, Technology, Communications— · 5
Credit— · 4
Housing and Community Development— · 4
Petroleum industry— · 4
Day care— · 3
Mines and mineral resources— · 3
Range management— · 3
Territories (U.S.)— · 3
District of Columbia— · 2
Government corporations— · 2
Government publications— · 2
Motor vehicles— · 2
Private Legislation— · 2
Sports and Recreation— · 2
Commemorations— · 1
Congressional oversight— · 1
Constitutional amendments— · 1
Dairy industry— · 1
Disaster relief— · 1
Economic stabilization— · 1
Federal advisory bodies— · 1
Heating— · 1
Intergovernmental fiscal relations— · 1
Lobbying— · 1
Monuments and memorials— · 1
Ships and shipping— · 1
Vietnamese Conflict— · 1

Also voted in 27 areas where the parties never split — never on a contested question: Animals, Arts, Culture, Religion, Awards, medals, prizes, Child welfare, Congressional-executive relations, Conservation of natural resources, Emergency Management, Executive reorganization, Explosives, Gold, Immigration, Interest, Lakes, Land use, Lead poisoning, Livestock, Medical supplies, Mobile homes, Native Americans, Postal rates and revenues, Postal service, Reclamation of land, Refugees, Revenue sharing, Right of privacy, Rivers, Strategic materials.

Service record

78th · 194394th · 1975
Democrat78th–82nd
Democrat83rd–94th

Party switchers

John Alexander LoganD→R · IL · 40thWesley Wade WatkinsD→R · OK · 105thBen Nighthorse CampbellD→R · CO · 104th
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