As I travel the country, many people tell me they wish they had been on the jury in the criminal trial of the shooting death of Trayvon Martin. I tell them that although they did not have a vote in those proceedings, they do have a vote in establishing Trayvon’s legacy. This vote, your vote, will be historic. It starts when you sign the Change.org petition by Trayvon’s family to amend “stand-your-ground” laws in 21 of the 31 states where they are on the books. It continues when you cast your vote in the 2014 midterm elections and each election...