If you remember right after 9/11/01 you had the anthrax attacks, letters with anthrax sent to people. If I remember correctly seven people died.
It's believed that the person who was responsible was an American scientist who committed suicide I think back in 2008.
The only reason I bring this up, that there are some who like to say these anthrax attacks were terrorist attacks on G.W. Bush's watch. Even though they had nothing to do with Al Qaeda or any other foreign terrorist organization.
By their definition the bomb that was intercepted that was addressed to Sheriff Joe Arpaio last week would also meet the definition of a attempted terrorist attack. The person or individuals who sent the bomb were very likely pro illegal alien, pro amnesty and pro open borders. Does that mean that all who support amnesty are terrorist ?
When ricin artillery shells along with mustard gas shells were found in Iraq during the Iraq war, the political left said that ricin didn't count as being a WMD.