Legality of Usage (per Public domain)

All video...

...from within the chambers of the United States Congress is exclusively filmed by C-SPAN. C-SPAN's copyright policy states, in part, "Video coverage of the debates originating from the chambers of the U.S. House of Representatives and the U.S. Senate is in the public domain and as such, may be used without restriction or attribution." Therefore this video is in the public domain as a US Government work.

https://en.wikipedia.org/wiki/Wikipedia:CSPAN