Perhaps it is that they do not have the will to investigate. Otherwise, why would DOJ drop the ball on the corrupt campaign finance issues?
There wouldn't be a campaign finance problem if politicians hadn't put their political power up for sale in the first place.
That is quite true, but we should not be surprised that so many are seduced by the power and percs. If the government's actions were consistent with limited Constitutional government, there would be far fewer ways for politicians and government to play favorites and aid contributors, which would make it less worthwhile for those seeking favors or special treatment to contribute.
Having said that, the campaign finance scandals that the campaign finance task force was supposed to investigate was not a campaign finance "problem" but has a matter of corruption and criminal behavior. Bush/Ashcroft simply dropped the ball on corruption here.