The group that lobbied to let the Federal Assault Weapons ban expire without renewal was the National Rife Association. President Bush let the ban expire.

Mitt Romney does not have the authority to unilaterally ban assault weapons.

The Federal Assault Weapons ban came into effect on the 13th September 1994. The law expired on the 13th September 2004. Some states still have a similar ban in effect.

The assault weapons ban worked in that it reduced the number of crimes committed with the banned guns, but it did not reduce crime overall.

No, this would require legislation from Congress. This is because currently there is no law banning assault weapons for an executive order to clarify the scope of.