Gun violence should be treated like a public health problem.

[petronius]

8. It was never a ban in the usual meaning of the word, but rather a proscription

on advocacy inserted into the appropriation bill for the CDC coupled with some (temporary, albeit obviously pointed and threatening) removal of funding. CDC interpreted those action as a full-on ban on research. Here's the text of the 'ban'

“None of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control.”

And here's an article from the Washington Post that gives a decent background...