So, with a little more research, OP discovered that Tim Kaine is sitting in front of an embroidery that depicts the Commonwealth of Virginia motto: Sic Semper Tyrannis ("Thus always with tyrants"), the seal of the commonwealth.
https://en.m.wikipedia.org/wiki/Sic_semper_tyrannis
https://en.m.wikipedia.org/wiki/Flag_and_seal_of_Virginia