Issa and Grassley pushed as hard as they could, given the complete lack of support they received from Boehner, McConnell and the rest of the Republican leadership, who never once dared step across the line and allow F&F to become a 2012 campaign issue.
They did, but they pushed in the wrong direction. They went for the brass ring, thinking they were Woodward and Bernstein.
The fact is, the Oval Office effectively insulated themselves, and the possibility of prosecuting those who actually engineered and carried out the operation (Voth, Gillette, McAllister) went out the window when executive privilege was invoked. Sure, there was a bit of scandal. Sure, some folks quit or got reassigned. But nobody got charged or prosecuted.
They should have gone after the Phoenix Division first, gotten a few folks to roll, then gone up the chain. Instead, they wanted to implicate the entire executive branch, and they failed.