“The day Obama gave the speech was July 27, 2004, Tish B’Av (9th of Av), the Jewish historical day of calamity and mourning.”
I did not know that about the date he gave his speech. Tish ab’v lasts 2 or 3 weeks or so, and falls in the summer. You aren’t allowed to get married during that time.
Tisha B’Av means the ninth day of the month of Av. You are referring to the three week period preceding Tisha B’Av which is a period of mourning culminating with Tisha B’Av, the day when all the worst calamities happened to the Jewish people. Mourning practices include not getting haircuts, not shaving, not listening to music and not having weddings. The last 9 days increase the mourning observances with prohibitions on bathing, washing clothes, eating meat and other observances.