Interestingly that seems to be a result of the CDC's own political leanings. They seemed to pursue the research with an explicit political goal, rather than research the effects of gun violence, and then find a goal[1]. Further, the Dickey amendment doesn't actually force the CDC to avoid researching the issue but rather preventing it from using federal money . to promote gun control:

"none of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention (CDC) may be used to advocate or promote gun control"[2]

[1]https://www.politico.com/agenda/story/2015/12/why-we-cant-tr... [2]https://en.wikipedia.org/wiki/Dickey_Amendment_(1996)

What if it turns out that research suggests gun control is effective in reducing gun violence? Note, I'm not saying that it is effective; I have no dog in this fight and don't know enough. But the law effectively says to the CDC "You're allowed to research this health issue, but if you come to a conclusion that's politically unacceptable, you can't share it."

The result is that the CDC now believes any gun violence research to be likely to result in political reprisal against them come budget time.[1]

1. https://www.washingtonpost.com/news/storyline/wp/2015/01/14/...

If you don't understand that barring a conclusion from receiving federal funding is effectively barring the research itself, then you don't understand academic research. Even if you legitimately don't find gun control to be a solution from your research, that you would lose your funding if you did means there is necessarily a financial incentive with no basis in fact to have or not have certain results - invalidating the research. The actual effect is that it bars research into gun violence, even if that is not the letter of the law.

[1] is an unsourced op-ed by a representative of the NRA's lobbying arm, who advocated for the amendment in the first place. Here's an opposing view:

http://www.apa.org/science/about/psa/2013/02/gun-violence.as...

Wow. Holy cow. Why aren't doctors pushing back politically on this?

They are:

https://www.huffingtonpost.com/entry/dickey-amendment-gun-vi...

The firearms industry wields a great deal of power in Washington through its lobbying and advocacy organization, the NRA.

I suspect the sets of actual doctors (I mean, those that work on healing people) and people wanting to use the mantle of CDC to institute gun control regulations have rather small intersection.