The legislative network of the 116th Congress (2019-2020)

The 116th Congress of the United States convened on January 3rd, 2019 and ended on January 3rd, 2021, giving way to the 117th Congress. Before looking forward to the accomplishments of the next Congress, it’s worth looking back at the record of the 116th Congress’s legislative accomplishments and the elected officials that made Washington work.

Over 15,000 bills were introduced in the House and Senate, 1,800 bills passed at least one chamber of Congress, 344 bills became law, and President Trump vetoed 10 bills.

Before moving onto a full network analysis of the 116th Congress, please find below some top-line metrics from the 116th Congress situated in comparative historical context.

The number of bills considered on the floor of both chambers of Congress has remained somewhat steady, but the number of bills passed into law has decreased by more than half over the past 40 years. The presidential veto power has been used more sparingly in recent decades, and almost exclusively during times of divided government - President Carter (1977-80) is a clear outlier in this respect.

Senate Legislative Network Analysis

Now, for the main subject of this article: the legislative network of Congress. The Senate and House are groups of individual senators and representatives that, taken together, form the Congress of United States. Much like a social network like Instagram or the human nervous system, representatives in Congress are connected through various relationships, such as political party or home state.

The primary role of senators and representatives is to legislate: to write and pass bills that ultimately become law. For those that need it, click here for a quick refresher on the legislative process. But senators and representatives don’t write and pass bills alone - they need to work with other elected officials to shepherd bills through committee, garner support for a floor vote, and pass their respective chambers.

These legislative relationships are best represented through the sponsor-cosponsor relationship:
1. For a bill to be submitted for consideration, at least one senator or representative must sponsor it. The first name on the bill is the sponsor, and all additional names are known as “original” cosponsors.
2. The sponsor of a bill can then recruit others to cosponsor the bill after introduction, indicating support and generating momentum.
3. A bill can have any number of cosponsors, and generally many more representatives will ultimately vote for a bill than cosponsor it.

Network analysis allows for a quantitative analysis of this legislative network. In a network, nodes are connected to each other through ties of varying directions and strengths. In this legislative network, the senators and representatives are nodes connected to each other through the bills they have sponsored and cosponsored.

The Senate legislative network above visualizes the sponsor-cosponsor relationship between senators for every bill that became law in the 116th Congress. The direction of the arrows illustrate the flow of cosponsorships from cosponsors to the original sponsor of a bill. Senators at the center of the network worked together more closely with a higher number of other senators than those at the further edges of the network. Clicking a particular senator’s node will highlight every senator they worked with to pass legislation in the 116th Congress.

Below, the chord diagram represents the sponsor-cosponsor relationship between Republicans, Democrats and the two Independents in the Senate.

Similar to the full network visualization prior, the arrows indicate the flow of cosponsorships from cosponsors to original bill sponsors. Though a healthy majority of bills passed were originally sponsored by a Republican (the GOP had Senate control in the 116th Congress), a fair number of passed legislation was sponsored by Democrats. Given the current 60 vote threshold in the Senate to overcome the filibuster and pass legislation, it’s not surprising a significant number of Democrats cosponsored Republican bills that became law, and vice-versa. This will look different in the majority-rule house further below.

The Influence of Individual Senators

Is it possible to know which senators were most important to the legislative process in the 116th Congress? It depends on your definition of “important” - most bills passed? The price tag of bills? If a bill was related to certain critical policy areas, such as national security or defense? In network analysis, the concept of centrality attempts to determine the importance of nodes. As there are various definitions of importance, there are various measurements of centrality.

Some standard centrality measurements include:
- degree: how many direct ties a specific node has to other nodes
- strength: the strength of the ties between a specific node and other nodes
- betweenness: how often a specific node lies on the shortest path between other nodes, i.e. the influence of a specific node across the entire network

In the case of this legislative network:
- degree: how many cosponsorships a specific senator recruited or extended
- strength: the strength of the ties between a specific senator and other senators
- betweenness: the influence of a specific senator across the entire legislative network

House Legislative Network Analysis

The same set of analyses as above, but for the House of Representatives.

In the majority-rule House, the number of bills that passed were sponsored by Democrats significantly more so than by Republicans (the Democrats regained control for the 116th Congress).

House Summary Stats and Centality Measurements

Can you find your representative?

Reference - All Bills Passed in 116th Congress

Questions or comments? Please reach out!

Data Source:

Created in R.