There are 78 questions tagged with house-of-representatives or senate which are also tagged congress.
There are 26 questions tagged with house-of-representatives and senate. Five of those questions are also tagged congress.
Therefore, 99 questions may be over-tagged depending on the usefulness of the tags for the question and whether the question relates to the US.
For comparison, there are 274 questions tagged with house-of-representatives or senate which are not tagged congress. Not all of those are for the US.
Should the [congress] tag be omitted when referring specifically to the [house-of-representatives] or the [senate]?
When referring to both the [house-of-representatives] and the [senate], should only the [congress] tag be used?
There being only 5 tags available for a question, freeing a tag would allow adding other tags, particularly, the [united-states] tag for some questions at the 5 tag limit.