Chuck Grassley

Senator · IA · R

Current term Jan 3, 2023 – Jan 3, 2029 · In the Senate since Jan 5, 1981

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.

Chuck Grassley · ChamberLens.org

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Chuck Grassley

Senator · IA · R

Current term Jan 3, 2023 – Jan 3, 2029 · In the Senate since Jan 5, 1981

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

81%

54 of 67 bills they sponsored had at least one original cosponsor from the other party.

Senate median 41% · Republicans 43%

Cosponsoring the other party's bills

34%

63 of 188 bills they cosponsored were introduced by a Democrat.

Senate median 19% · Republicans 18%

Voting with own party

99%

On 819 party-line votes, voted with most Republicans 814 times.

Senate median 99% · Republicans >99%

Voting with the other party

On 869 contested votes, voted the same way as most Democrats 53 times.

Senate median 6% · Republicans 6%

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 J. DurbinDIL13 of theirs · 14 of this member's
Joni ErnstRIA14 of theirs · 9 of this member's
Amy KlobucharDMN6 of theirs · 16 of this member's
John CornynRTX12 of theirs · 8 of this member's
Margaret Wood HassanDNH2 of theirs · 17 of this member's
Catherine Cortez MastoDNV6 of theirs · 9 of this member's
James LankfordROK6 of theirs · 9 of this member's
Marsha BlackburnRTN4 of theirs · 11 of this member's
Ted CruzRTX5 of theirs · 9 of this member's
Thom TillisRNC4 of theirs · 10 of this member's

Across the aisle (Democrats)

Richard J. DurbinDIL13 of theirs · 14 of this member's
Amy KlobucharDMN6 of theirs · 16 of this member's
Margaret Wood HassanDNH2 of theirs · 17 of this member's
Catherine Cortez MastoDNV6 of theirs · 9 of this member's
Jeanne ShaheenDNH3 of theirs · 8 of this member's
Raphael G. WarnockDGA

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

James LankfordROK99% · 860 of 865
Pete RickettsRNE99% · 857 of 862
Tim ScottRSC99% · 838 of 843
John HoevenRND99% · 856 of 862
David McCormickRPA99% · 839 of 845

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 (18). Furthest along first.

Became lawS. 3705Semiquincentennial Congressional Time Capsule Act
Original cosponsor · sponsored by Thom Tillis · original backers: 2 D, 2 R · became law Feb 18, 2026
Became lawS. 222Whole Milk for Healthy Kids Act of 2025
Original cosponsor · sponsored by Roger Marshall · original backers: 4 D, 7 R · became law Jan 14, 2026
Became lawS. 331HALT Fentanyl Act
Original cosponsor · sponsored by Bill Cassidy · original backers: 7 D, 10 R · became law Jul 16, 2025
Passed the SenateS. 2677A bill to expand the sharing of information with respect to suspected violations of intellectual property rights in trade.
Sponsor · original backers: 1 D, 1 R · passed the Senate Aug 7, 2026
Passed the SenateS. 3977Bankruptcy Threshold Adjustment Act of 2026
Sponsor · original backers: 3 D, 3 R · passed the Senate Aug 3, 2026

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

81%

54 of 67 bills they sponsored had at least one original cosponsor from the other party.

Senate median 41% · Republicans 43%

Cosponsoring the other party's bills

34%

63 of 188 bills they cosponsored were introduced by a Democrat.

Senate median 19% · Republicans 18%

Voting with own party

99%

On 819 party-line votes, voted with most Republicans 814 times.

Senate median 99% · Republicans >99%

Voting with the other party

On 869 contested votes, voted the same way as most Democrats 53 times.

Senate median 6% · Republicans 6%

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 J. DurbinDIL13 of theirs · 14 of this member's
Joni ErnstRIA14 of theirs · 9 of this member's
Amy KlobucharDMN6 of theirs · 16 of this member's
John CornynRTX12 of theirs · 8 of this member's
Margaret Wood HassanDNH2 of theirs · 17 of this member's
Catherine Cortez MastoDNV6 of theirs · 9 of this member's
James LankfordROK6 of theirs · 9 of this member's
Marsha BlackburnRTN4 of theirs · 11 of this member's
Ted CruzRTX5 of theirs · 9 of this member's
Thom TillisRNC4 of theirs · 10 of this member's

Across the aisle (Democrats)

Richard J. DurbinDIL13 of theirs · 14 of this member's
Amy KlobucharDMN6 of theirs · 16 of this member's
Margaret Wood HassanDNH2 of theirs · 17 of this member's
Catherine Cortez MastoDNV6 of theirs · 9 of this member's
Jeanne ShaheenDNH3 of theirs · 8 of this member's
Raphael G. WarnockDGA

Voting most alike

Most alike

James LankfordROK99% · 860 of 865
Pete RickettsRNE99% · 857 of 862
Tim ScottRSC99% · 838 of 843
John HoevenRND99% · 856 of 862
David McCormickRPA99% · 839 of 845

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 (18). Furthest along first.

Became lawS. 3705Semiquincentennial Congressional Time Capsule Act
Original cosponsor · sponsored by Thom Tillis · original backers: 2 D, 2 R · became law Feb 18, 2026
Became lawS. 222Whole Milk for Healthy Kids Act of 2025
Original cosponsor · sponsored by Roger Marshall · original backers: 4 D, 7 R · became law Jan 14, 2026
Became lawS. 331HALT Fentanyl Act
Original cosponsor · sponsored by Bill Cassidy · original backers: 7 D, 10 R · became law Jul 16, 2025
Passed the SenateS. 2677A bill to expand the sharing of information with respect to suspected violations of intellectual property rights in trade.
Sponsor · original backers: 1 D, 1 R · passed the Senate Aug 7, 2026
Passed the SenateS. 3977Bankruptcy Threshold Adjustment Act of 2026
Sponsor · original backers: 3 D, 3 R · passed the Senate Aug 3, 2026

Chuck Grassley

Working relationships

Chuck Grassley

Working relationships

Closest collaborators

All colleagues

Across the aisle (Democrats)

Voting most alike

Most alike

Bipartisan bills that advanced

Closest collaborators

All colleagues

Across the aisle (Democrats)

Voting most alike

Most alike

Bipartisan bills that advanced

Most alike among Democrats