Not all the planned amendments are yet public, but Rep. Tony Cardenas, D-CA, has said he plans to offer one to lift what many have described as a ban on federal research into gun violence.

In fact, what Cardenas’ amendment is targeting is a provision that was attached to a 1996 appropriations bill by Republicans at the behest of the National Rifle Association, which was unhappy with research by the Centers for Disease Control that found that gun ownership increased risk of injury. But the provision only forbade the CDC from using federal funds to “advocate or promote gun control.” Since the law was passed however, the CDC has generally steered clear of gun-related research.

Obviously, it is unlikely that any gun-related measures put forward by Democrats will get any support from the majority party. And even some Democrats seem uninterested in pursuing the gun debate, for fear that it might derail one of the few examples of meaningful bipartisan legislation in recent years.

Related: Mental health takes back seat in most health plans

To gain Democratic support for the bill, Rep. Tim Murphy, R-PA, sacrificed a provision of the original legislation that would have given caregivers greater access to the medical records of those getting drug treatment. Some argued the provision endangered patient privacy.

The bill will establish an assistant secretary of the Department of Health and Human Services focused on mental health. That person will lead a new office within the agency that will lead research and psychological treatment programs.

Murphy rejected calls for guns to enter the discussion over his mental health legislation.

“This is a disease, mental illness,” Murphy told The Hill. “I don't want to see us taint it or demean it to say, ‘Let's just talk about an object.’ That takes away from the importance and the meaningfulness of what people are suffering.”