Mazie K. Hirono

Senator · HI · D

Current term Jan 3, 2025 – Jan 3, 2031 · In the Senate since Jan 3, 2013

Official website Contact form Biographical Directory

Portrait: U.S. Government Publishing Office, via unitedstates/images (public domain)

Working relationships

How often this member works with colleagues across party lines, from bill sponsorships and recorded votes in this Congress. Bills are H.R., S., H.J.Res. and S.J.Res.; resolutions, post office namings, and Congressional Gold Medal and commemorative coin bills are left out. Independents are counted with the party they caucus with. These figures describe the public record; they do not measure effectiveness or ideology.

Mazie K. Hirono · ChamberLens.org

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Mazie K. Hirono

Senator · HI · D

Current term Jan 3, 2025 – Jan 3, 2031 · In the Senate since Jan 3, 2013

Official website Contact form Biographical Directory

Portrait: U.S. Government Publishing Office, via unitedstates/images (public domain)

Working relationships

119th Congress, Senate.

Bills with other-party backing

15%

6 of 40 bills they sponsored had at least one original cosponsor from the other party.

Senate median 41% · Democrats 35%

Cosponsoring the other party's bills

15%

58 of 399 bills they cosponsored were introduced by a Republican.

Senate median 19% · Democrats 22%

Voting with own party

99%

On 836 party-line votes, voted with most Democrats 825 times.

Senate median 99% · Democrats 96%

Voting with the other party

On 889 contested votes, voted the same way as most Republicans 40 times.

Senate median 6% · Democrats 8%

Closest collaborators

Counted both ways: bills by the colleague that this member cosponsored, and bills by this member that the colleague cosponsored.

All colleagues

Richard BlumenthalDCT29 of theirs · 11 of this member's
Alex PadillaDCA21 of theirs · 13 of this member's
Elizabeth WarrenDMA21 of theirs · 13 of this member's
Edward J. MarkeyDMA23 of theirs · 9 of this member's
Cory A. BookerDNJ18 of theirs · 13 of this member's
Richard J. DurbinDIL19 of theirs · 11 of this member's
Tammy DuckworthDIL15 of theirs · 12 of this member's
Brian SchatzDHI12 of theirs · 12 of this member's
Chris Van HollenDMD11 of theirs · 11 of this member's
Jeff MerkleyDOR12 of theirs · 10 of this member's

Across the aisle (Republicans)

Lisa MurkowskiRAK8 of theirs · 1 of this member's
Jerry MoranRKS6 of theirs · 1 of this member's
Dan SullivanRAK4 of theirs · 2 of this member's
John CornynRTX5 of theirs · 0 of this member's
Susan M. CollinsRME2 of theirs · 2 of this member's
Thom TillisRNC

Voting most alike

Contested roll calls (at least 10% of yea and nay votes on the losing side) on which both voted yea or nay, and how often they made the same choice. Colleagues who shared too few of these votes with this member are not ranked.

Most alike

Lisa Blunt RochesterDDE97% · 860 of 884
Patty MurrayDWA97% · 818 of 841
Chris Van HollenDMD97% · 848 of 875
Edward J. MarkeyDMA97% · 854 of 883
Jeff MerkleyDOR96% · 851 of 882

Bipartisan bills that advanced

Bills this member sponsored or joined as an original cosponsor, with original backers from both parties, that passed at least one chamber (4). Furthest along first.

Became lawS. 260Bottles and Breastfeeding Equipment Screening Enhancement Act
Original cosponsor · sponsored by Tammy Duckworth · original backers: 2 D, 2 R · became law Nov 25, 2025
Became lawS. 2392Veterans’ Compensation Cost-of-Living Adjustment Act of 2025
Original cosponsor · sponsored by Jerry Moran · original backers: 9 D, 7 R · became law Nov 25, 2025
Passed the SenateS. 787VetPAC Act of 2025
Original cosponsor · sponsored by Bill Cassidy · original backers: 1 D, 1 R · passed the Senate Dec 18, 2025
Passed the SenateS. 3436Caring for Veterans and Strengthening National Security Act
Original cosponsor · sponsored by Jerry Moran · original backers: 5 D, 5 R · passed the Senate Dec 17, 2025

Each member's party on each date comes from congress-legislators term records. Party-line votes are roll calls on which most voting Democrats and most voting Republicans took opposite sides; procedural votes are included. The Vice President's tie-breaking votes and impeachment verdicts are not counted, and a bill enacted as part of another bill counts only at the stage it reached on its own. Medians include everyone who served in the chamber this Congress with enough records (5 sponsored bills, 10 cosponsorships, 25 votes). Computed Oct 23, 2026, 11:51 AM ET from Congress.gov and House and Senate roll calls.

119th Congress, Senate.

Bills with other-party backing

15%

6 of 40 bills they sponsored had at least one original cosponsor from the other party.

Senate median 41% · Democrats 35%

Cosponsoring the other party's bills

15%

58 of 399 bills they cosponsored were introduced by a Republican.

Senate median 19% · Democrats 22%

Voting with own party

99%

On 836 party-line votes, voted with most Democrats 825 times.

Senate median 99% · Democrats 96%

Voting with the other party

On 889 contested votes, voted the same way as most Republicans 40 times.

Senate median 6% · Democrats 8%

Closest collaborators

Counted both ways: bills by the colleague that this member cosponsored, and bills by this member that the colleague cosponsored.

All colleagues

Richard BlumenthalDCT29 of theirs · 11 of this member's
Alex PadillaDCA21 of theirs · 13 of this member's
Elizabeth WarrenDMA21 of theirs · 13 of this member's
Edward J. MarkeyDMA23 of theirs · 9 of this member's
Cory A. BookerDNJ18 of theirs · 13 of this member's
Richard J. DurbinDIL19 of theirs · 11 of this member's
Tammy DuckworthDIL15 of theirs · 12 of this member's
Brian SchatzDHI12 of theirs · 12 of this member's
Chris Van HollenDMD11 of theirs · 11 of this member's
Jeff MerkleyDOR12 of theirs · 10 of this member's

Across the aisle (Republicans)

Lisa MurkowskiRAK8 of theirs · 1 of this member's
Jerry MoranRKS6 of theirs · 1 of this member's
Dan SullivanRAK4 of theirs · 2 of this member's
John CornynRTX5 of theirs · 0 of this member's
Susan M. CollinsRME2 of theirs · 2 of this member's
Thom TillisRNC

Voting most alike

Most alike

Lisa Blunt RochesterDDE97% · 860 of 884
Patty MurrayDWA97% · 818 of 841
Chris Van HollenDMD97% · 848 of 875
Edward J. MarkeyDMA97% · 854 of 883
Jeff MerkleyDOR96% · 851 of 882

Bipartisan bills that advanced

Bills this member sponsored or joined as an original cosponsor, with original backers from both parties, that passed at least one chamber (4). Furthest along first.

Became lawS. 260Bottles and Breastfeeding Equipment Screening Enhancement Act
Original cosponsor · sponsored by Tammy Duckworth · original backers: 2 D, 2 R · became law Nov 25, 2025
Became lawS. 2392Veterans’ Compensation Cost-of-Living Adjustment Act of 2025
Original cosponsor · sponsored by Jerry Moran · original backers: 9 D, 7 R · became law Nov 25, 2025
Passed the SenateS. 787VetPAC Act of 2025
Original cosponsor · sponsored by Bill Cassidy · original backers: 1 D, 1 R · passed the Senate Dec 18, 2025
Passed the SenateS. 3436Caring for Veterans and Strengthening National Security Act
Original cosponsor · sponsored by Jerry Moran · original backers: 5 D, 5 R · passed the Senate Dec 17, 2025

Mazie K. Hirono

Working relationships

Mazie K. Hirono

Working relationships

Closest collaborators

All colleagues

Across the aisle (Republicans)

Voting most alike

Most alike

Bipartisan bills that advanced

Closest collaborators

All colleagues

Across the aisle (Republicans)

Voting most alike

Most alike

Bipartisan bills that advanced

Most alike among Republicans