Why isn't there intercommunion with Protestants?

Why is Protestant communion invalid? And as a Protestant why can I not take communion in the Catholic Church?

This link should be helpful for understanding Communion and Protestants. If you have any further questions or concerns that are not answered by these links, please contact Catholic Answers directly.

Recommended Reading:

[LIST]
*]Ecclesia de Eucharistia (Note especially sections 43-46)
*]Who Can Receive Communion?
*]May I receive Communion with Lutherans?
*]Why can’t Catholics receive Protestant communion?
[/LIST]

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit www.catholic.com.