In the past, law enforcement (ATF) has allowed straw buyers to complete the transaction so they can be closely surveilled while passing the firearm to the criminal.
But if there was any chance of losing the firearm, they would intercept immediately. Hence, none were lost.
Under Project Wide Receiver (Bush43) the ATF worked with the Mexican government. A straw purchase would be allowed and the buyer would be surveilled crossing the border where Mexican authorities were waiting to intercept.
On one occasion, the Mexicans failed to stop a truck with 300 firearms on board. The program was shut down immediately.
Under Fast & Furious, the ATF made no attempt to follow the straw buyer. There was no coordination with Mexican authorities. In fact, Mexican authorities were never told that firearms were pouring across the border through this program.
Some of the straw buyers were "informants" for the FBI or DEA. Those straw buyers were using taxpayer funds to purchase the weapons that were passed on to drug cartels. So, even if stopped, those straw buyers could never be prosecuted.
Hannity had Michelle Malkin and that liberal loon Tamara Holder. Listen to what that lunatic claims.
Eric Holder obstructing Justice? She starts at the 0:3:58 minute time line