Everyone who is concerned about a lack of gun law enforcement ought to be agitating in favor of adequate staffing and funding for the agencies tasked with enforcement. Many federal agencies fail to perform their missions better because they lack adequate funding. Hamstringing an agency with inadequate funding fulfills the far right's prophecy that government is a waste of time and money.
The executive branch has a lot to say about how that money is spent. They can use the money for the Border Patrol to hire border guards or they can use it to set up a program where illegal aliens get SS numbers and work permits, "pending deportation".
They can spend money on prosecuting felons who try to beat the NICS check or they can spend money on programs for selling firearms to gunrunners for export to Mexico as in "Fast and Furious".
They can spend money on investigating urban gangs as organized crime and prosecuting them under RICO statutes. Or they can investigate George Zimmerman for shooting Trayvon Martin as Mr. Martin sat astride Zimmerman, performing a MMA ground and pound on Mr. Zimmerman's head. Or they can investigate the Feruguson police department because a White policeman shot a strong armed robber who was charging him.
Mr. Obama's Attorney General has been traveling the country, "negotiating" consent decrees with various police departments. Of course she could have used that money to help Chicago get control of its gangs. Murders are up, through May, 46% from the same period last year and up 72% from the year before that. But those Chicago cops have got Ms. Lynch looking over their shoulder as they patrol that city infested with habitual violent criminals ("thug" is now a "dog whistle" word and is politically incorrect and racist).
So I think Obama's and Lynch's priorities are the main problem, funding less so.