How to read a roll call vote
What the tally does and does not tell you.
A roll call records how each member voted on a specific question at a specific moment. It is the most reliable data in legislative politics and the most frequently misread.
Read the question first
The question is not always "should this bill pass". It may be a motion to table (kill), a motion to recommit (send back to committee), a procedural rule, or a cloture motion. A member voting no on a procedural motion may support the underlying bill.
Not voting is not the same as abstaining
Members miss votes for travel, illness, and scheduling. A "not voting" entry is a fact about attendance, not a position. We display it separately from present votes for that reason.
Margin matters more than the total
A 218–214 vote and a 400–30 vote both say "Passed". The first tells you the outcome depended on two members; the second tells you it did not. We flag votes decided by five or fewer.
Party splits describe, they do not explain
We show how many members of each party voted each way because it is in the record. We do not characterize a vote as a party-line vote or a defection, because those words carry a judgment about what a member owed their party.