I think it would be convenient if the gubbermint enforced the laws already enacted to prevent the mentally ill from obtaining firearms.  

"Since 1968, federal law has barred the possession or acquisition of firearms by anyone who “has been adjudicated as a mental defective or has been committed to any mental institution.”

In January 2008, President George W. Bush signed the bipartisan “NICS Improvement Amendments Act of 2007  All federal firearm licensees are required to check the system (either directly or through a state point of contact) before proceeding with a sale.  To accomplish this task, the legislation authorized federal grants to states that improve their record keeping and supply those records to NICS.

A law which isn't enforced is non-existent for all practical purposes.  Whining about gun ownership while not enforcing already required reporting for financial reasons or worrying about 'stigmatizing' the mentally ill is hypocricy...the kind that gets people killed.