Analysis · October 21, 2026

What cosponsoring a bill means, and who does it most

A typical House member cosponsors about 250 bills a Congress; some cosponsor more than 1,000 and a few fewer than 10. What cosponsorship signals and how it counts toward a grade.

Every bill in Congress has one sponsor, the member who introduces it. It can also have any number of cosponsors, members who add their names to show support. Cosponsorship is one of the most common things members do: current members of the House and Senate have recorded more than 140,000 cosponsorships of bills and joint resolutions in the 119th Congress. It makes up the "bills supported" score on each report card, which counts for 25% of the overall grade.

How cosponsoring works

A member can sign on as an original cosponsor when the bill is introduced, or add their name at any point afterward. There is no vote and no debate. A member's office simply notifies the clerk. Sponsors often recruit cosponsors by circulating a "Dear Colleague" letter describing the bill, and advocacy groups regularly ask members to sign on to bills they support.

Cosponsoring signals several things. It tells the bill's sponsor and committee chair that the bill has support, which matters when they decide which bills to move. It tells constituents and advocates where a member stands. And bipartisan cosponsor lists are often a sign that a bill has a real chance, because they show it can draw votes from both sides.

What cosponsoring does not do is commit a member to vote for the final bill. Bills change as they move through committee, and members sometimes vote against bills they cosponsored after amendments they oppose. It also does not mean the member did any work on the bill. Some cosponsors help write and promote a bill; others add their names and do nothing more.

How much members cosponsor

Cosponsorship totals vary far more than any other number on the report card. In the House, the typical member who has served the full Congress has cosponsored about 257 bills. But the spread is wide:

The Senate is more compact. The typical senator has cosponsored about 146 bills, and no senator has reached 600.

The most active cosponsors

In the House, the most active cosponsor by a wide margin is Eleanor Holmes Norton, the delegate from the District of Columbia, with 1,686 bills. Delegates can't vote on final passage of bills, so cosponsoring is one of the main ways they can register support. Among voting members, the leaders are Brian K. Fitzpatrick of Pennsylvania (1,106), Eugene Simon Vindman of Virginia (1,011), Michael Lawler of New York (980), Rashida Tlaib of Michigan (965) and Shri Thanedar of Michigan (902).

In the Senate, the most active cosponsors are Peter Welch of Vermont (516), Alex Padilla of California (515), Chris Van Hollen of Maryland (494), Adam B. Schiff of California (485), Marsha Blackburn of Tennessee (417) and Tammy Duckworth of Illinois (415).

The list of top cosponsors mixes members who are known for bipartisan deal-making with members who are known for strong partisan positions. Cosponsoring a lot isn't tied to any one style. Some members sign on to almost every bill from their own party's caucus; others sign on to many bills across the aisle.

The least active cosponsors

At the other end are members who rarely cosponsor. Several are party leaders. Speaker Mike Johnson has cosponsored 3 bills and Majority Leader Steve Scalise 4, and Judiciary Committee chairman Jim Jordan has cosponsored 17. By tradition the Speaker rarely cosponsors or even votes, and leaders often avoid attaching their names to bills so they can stay neutral among their members' competing priorities. Why party leaders score low on bills covers this in more detail.

In the Senate, the least active cosponsors include Mitch McConnell of Kentucky (30), Ron Johnson of Wisconsin (34), Majority Leader John Thune of South Dakota (42) and Rand Paul of Kentucky (58).

Members who joined partway through the Congress also have low totals because they have had less time. Aisha Wahab of California, sworn in on September 2, 2026, has cosponsored 3 bills so far. Those members carry a partial term label on their report cards.

Party differences

Democrats cosponsor more than Republicans in both chambers. In the House, the median Democrat has cosponsored 340 bills and the median Republican about 189. In the Senate, the figures are 184 and 145. Part of the difference is a matter of party culture. Part of it may reflect being in the minority: members of the minority party have fewer chances to move their own bills, so signing on to others' bills is a larger share of their legislative activity.

How cosponsorship counts toward a grade

Because the totals vary so widely, Congress Report Card doesn't use raw counts. A member's cosponsorship total is ranked against their own chamber: the member with the most scores 100, the median member scores 75 and the member with the fewest scores 50. That keeps one member with 1,600 cosponsorships from flattening everyone else onto the bottom of the scale.

The weight is 25%, the lowest of the three scores. That reflects the fact that cosponsoring takes less effort than writing a bill or showing up to vote. It still counts, because it is a public, recorded commitment, and it is one of the few ways to see which issues a member chooses to put their name behind.

If you think cosponsoring deserves more or less weight, use Adjust grading on the home page to set your own weights. The grades will update instantly for every member.

Figures are from the Congress Report Card data as of October 21, 2026. Grades change as Congress votes, so the numbers on member pages may have moved since. How grades are calculated.