Researchers Curtis Miller and Jignesh Rawal developed an interactive map and scatter chart illustrating the relationships U.S. senators have with their colleagues, and despite the seemingly unbreakable partisan rhetoric nationwide, the display shows a surprising amount of general agreement among senators.
The program allows users to click on each state, then see with what frequency individual senators or other states’ delegations “agree” with that selected state’s delegation.
The program also allows users to isolate individual senators and find the rate with which other senators and delegations agree with them.
Unsurprisingly, blue states often show higher agreement rates among other blue states and Democratic senators, while red states often show higher agreement rates among other red states and Republican senators.
That would be expected, considering fellow party members generally share at least broadly similar ideologies, otherwise they wouldn’t be in the same party.
What could be considered somewhat surprising is how many states show relatively high agreement rates across the aisles.
No fewer than 92 of the 100 members of the U.S. Senate agree with Maine Republican Susan Collins the majority of the time (more than 50 percent of the time).
Of the eight who agree with Collins 50 percent of the time or less, seven are fellow Republicans. Five — Vermont independent Bernie Sanders (running as a Democrat), plus Ted Cruz, Rand Paul, Lindsey Graham and Marco Rubio — are in the 2016 presidential race.
The agreement rates, as used in this study, are how frequently senators vote the same way. As the five senators above are spending much of their time on the campaign trail, they’re missing more votes than most of their colleagues, and those vacancies are likely skewing their percentages in this display.
Maine’s other U.S. senator, independent Angus King, finds agreement a majority of the time from 86 — all but 14 — of his fellow senators.
Here’s how Miller and Rawal explained their findings:
“When looking at agreements for various senators, we see that for senators close to the extremes, there is a linear relationship between agreement rate and ideology, which is not surprising (ideology is computed via dimensionality reduction, so agreement rate and ideology contain some of the same information). What is more interesting are members not at the extremes. We initially thought that we would see a low correlation for members not at the extreme, with ‘low correlation’ meaning a cloud-like scatterplot. What we actually found was that more moderate members do have a relationship with the votes of other members: they are more likely to agree with other moderates and less likely to agree with extremists, so the scatterplot has a mountain-like shape for moderates.”
Along the ideological spectrum, the researchers placed Ron Wyden and Jeff Merkley, both Oregon Democrats, as the most liberal voters. Miller and Rawal placed Republicans Richard Shelby of Alabama and James Risch from Idaho at the far right end of the political range.
Collins is depicted as almost dead center in the scatter chart, in terms of political leanings, with only two Republicans to the left of her and one Democrat to the right of her. King is placed in the leftmost third of the grid, with 39 Democrats and the aforementioned Sanders to the left of him, and five Democrats (as well as the entire GOP) to the right of him.