No, the ban was making it's way to SCOTUS

this pre-dated Heller and McDonald so lower courts were ruling blind and politically and probably ruled to push cases to SCOTUS for precedent. The SCOTUS standard is very simple. If a weapon is "in common use for lawful purposes" it cannot be singled out and restricted...around 100 million in private hands with competitive shooting competitions every weekend from coast to coast satisfies that requirement.

Why do you suppose a Democratic Senate and Congress failed to renew the ban?

No, every term without exception in every law is unambiguously defined for the purposes of the law....there are few "common definitions" in law when it comes to terms as opposed to single words. There is no definition of "assault weapon" that isn't inclusive of common 1950's hunting rifles even if modern rifles were not already so prolific in society.

In 2004 there were cases getting close to SCOTUS which were going to set irreversible precedent. Those who supported the AWB did not renew the ban because of the almost certain loss. Which is also why GWShrub happily repeated that he would sign an assault weapons ban renewal and nary Washington repug objected to the newly elected president bush agreeing to sign the extension.

The reason Dems and gun control decided not to renew was to make another run at an AWB at a later date...maybe now...without prohibitive precedent could find a solution or at leaat another sunset law..

The issue remains exactly what we saw in CA just now. CA has the strongest assault weapons law in the US, yet the guns used in SB were CA legal. They are legal because a law which would make them illegal would also make illegal grandpa's 1940's hunting rifle...hundred millions....

"In common use for lawful purposes" is the standard set by SCOTUS as the line between guns which can be heavily restricted and those which are constitutionally protected.."sawn off shotgun" vs. Standard barrel shotgun USA v. Miller 1934 (iirc).

There was also the issue of restriction on enumerated civil rights must show demonstrable benefit to society and there were no supporting statistics for the 10 year ban indicating any impact on society good or bad.