Operation Fast and Furious

It's not the cover-up, it's the crime;

Operation Fast and Furious was specifically conceived so that “walked” guns would be recovered at crime scenes in Mexico. Their serial numbers would be provided to the ATF by Mexican authorities for tracing. Regardless of motive, the entire operation was premised on weapons being recovered at crime scenes in Mexico, and law enforcement agencies are well aware that criminals primarily abandon weapons only after they’ve been used in serious felony crimes such as murder or attempted murder.
Operation Fast and Furious was conceived knowing that Mexican nationals would be sacrificed in significant numbers if the tracing operation had any chance of working.
Operation Fast and Furious allowed more than 2,000 weapons to “walk,” indicating that those in charge of the operation were willing to let thousands of Mexican nationals die in an effort to identify the ringleaders of a cartel’s weapon acquisition team.

And it could only happen under a Democratic administration, because only a Democratic administration could rely on a free pass by media.
Via Instapundit