You have the power to break up criminal organizations, stop terrorism groups, investigate acts of arson, prevent illegal firearms sales and protect American citizens. However, the ATF struggles with getting enough power to conduct investigations and perform their job. For example, legitimate gun dealers like Don's Friendly Assault Weapons do not have to report anyone buying a large cache of assault rifles. The law only requires that gun dealers report the sale of more than one handgun to the same person in a five-day span. Drug cartels aren't interested in hand guns, so the problem is that the ATF is never alerted when assault weapons are sold.
Furthermore, the ATF is allowed to review a gun dealer's records once every year. The lack of reporting makes it easy for criminals to swing by and load up the truck with AK-47s before hitting the McDonald's. All efforts to strengthen gun laws have petered out.
Therefore, the ATF doesn’t have enough manpower to bust legal and illegal firearms sales. The ATF puts straw buyers (the people buying the guns) under surveillance when it looks like they are conducting illegal activity. When a straw buyer purchases a gun, they must sign a form (under law) declaring that the gun is for them and will not be sold. It is the ATF's job to prove that the straw buyer is lying, but they must be able to prove that the person was intending to sell the gun before they signed the form. It’s kind of difficult to read minds.
While the fight for stricter gun laws is still going on in Congress, the ATF is trying to make do with the amount of power that they have. That being said, the ATF is not immune to abuses of power.
In recent years, the ATF has been criticized for searching people's property with a warrant, falsifying documents, and giving inaccurate testimonies. The ATF has to deal with some rotten apples.