The term "assault weapon" is a loose definition with too many variables.
What is considered an assault weapon in one state is not so in another and in most cases the term is applied to a weapon that merely resembles a military style firearm.
In the United States we aren't supposed to act against something because of the way it looks.
Until a nationally recognized, clear and reasonable definition of the term assault weapon exists on the books, such laws looking to ban these firearms cannot be passed. Agreement must be made by each state and federal agency with jurisdiction over firearms related issues.