Sen. Bob Casey (D-Pa.) has joined forces with Cartoon Network to help launch the net’s next initiative of its anti-bullying campaign.

Stop Bullying: Speak Up was jump-started in 2010 as a direct response to the concerns of the net’s auds, which claimed bullying was a major problem.

Casey joined Cartoon Network’s prexy Stuart Snyder at a Warren G. Harding Middle School rally in Philadelphia today to reveal specially designed flags, which represent a national flag-raising campaign — signifying environments where bullying is not tolerated — and will be sent to more than 2,000 upper elementary and middle schools through the American Federation of Teachers.

Casey’s partnership with the net comes in preparation of his reintroduction of the Safe Schools Improvement Act, which he says is a crucial step toward ensuring that no child is afraid to go to school for fear of bullying.

“We hope wherever the Stop Bullying: Speak Up flag might appear, young people will understand that this is a safe place where bullying behaviors will not be tolerated,” added Snyder.

Net’s campaign also includes an online social pledge app in partnership with Facebook and Time Warner, Inc., a nationally broadcast TV docu, a number of TV PSAs, two CNN specials and an online portfolio of educational resources on StopBullyingSpeakUp.com.

Rally is the latest in a continuing series that included youth-focused events with the governor of Maryland, HHS secretary and mayor of Atlanta.