Today’s politics have seen the parties become more polarized with each accusing the other of failing to be bi-partisan. But how bi-partisan are the parties? Is one more bi-partisan than the other? We crunch the numbers.


To explore the partisanship of each party we need to define what it is we are attempting to measure and compare. Partisanship is described as “prejudice in favor of a particular cause; bias” by An individual in the impeachment process could be considered partisan if they voted the way their party was expected to vote. This, however, does not account for those individuals that vote in the same direction for nonpartisan reasons. Absent the ability to understand those voting for their party we can, with some level of confidence, state that those voting against their party are not voting in a partisan manner. This being the case we should measure those voting against their party as an indication of being less partisan. Votes with the most party crossover would be considered less partisan, or more bi-partisan.

To see which party is more bi-partisan we will consider each vote from the Republican’s point of view. If the vote was pro-Republican then those Democrats voting for the bill would be considered bi-partisan, and visa versa. The opposite would be true for votes deemed pro-Democrat. Due to data constraints, we will evaluate the votes in aggregate. If a pro-Republican vote had 60 yes votes but the Senate only contains 52 Republicans, we would consider the vote to be bi-partisan for 7 Democrats; 60 votes minus 52 Republicans and 1 Independent. Because we are evaluating the parties as a whole rather than the individuals in the parties this aggregate or net technique serves our purpose of evaluating who the most bi-partisan party is.

For this exercise, we will evaluate what many consider the most important single legislative body in the country, the Congress. Specifically, the current Congress, the 116th Congress (2019-2020). The House has held 62 votes and Senate has held 30 votes for a total of 90 votes. The house is comprised of 232 Democrats, 198 Republicans, and 2 Independents. The Senate 45 Democrats, 52 Republicans., 1 Independent and 4 vacancies.

The Numbers 

In total, between both chambers of Congress, 92 votes were held. Of those 92 votes, 57 had at least one vote that crossed party lines in at least one chamber leaving 35 or 38% of votes falling onto partisan lines.

The Most Bi-Partisan Votes

The most bi-partisan vote came in the form of the United States-Mexico-Canada trade agreement or USMCA vote with 187 House Democrats crossing party lines to support the measure. The next largest bi-partisan effort from Congress came in the form of Motion to table articles of impeachment against President Trump with 134 Democrats crossing party lines to support the measure. In third, we found that the measure disapproving of the Trump administration’s plan to lift sanctions on three Russian companies with 130 Republicans crossing party lines. Finally, the fourth largest bi-partisan effort in Congress was the measure opposing President Trump’s withdrawal of troops from Syria with 122 Republicans crossing party lines. 

 The Nature of Bi-Partisan Voting

We found that the voting characteristics of each party varied widely. Democrats tended to vote in a block. Bi-partisan votes from Democrats in the House averaged 70 Democrats crossing party lines when they crossed. The opposite was true for Republicans who averaged 16 votes in the House when they crossed party lines and 12 votes in the Senate. However, between both chambers, we found that Democrats crossed party lines far less frequently, only 6 times, whereas Republicans crossed party lines 57 times.

In total, we found that, in the House and net, Democrats crossed party lines 421 times. House Republicans crossed party lines 556 times. In the Senate, we found that Democrats did not cross party lines once since the inception of the 116th Congress. Republicans crossed party lines 278 times in the Senate.

Bi-partisanship of the 116th Congress

The Results 

If we weight these numbers by the appropriate membership in each chamber, we found that, in the House, Democrats were on average 3% bi-partisan. Republicans were 5% bi-partisan. In the Senate Democrats were not bi-partisan or 0% and Republicans were 17% bi-partisan. Averaging these numbers shows that Congressional Democrats were bi-partisan 1.5% of the time and Congressional Republicans were bi-partisan 11% of the time.