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...