Lois Lerner has taken the Fifth Amendment. Though she cannot necessarily be fired for that, at the very least, she oversaw the Exempt Organizations Office at the IRS when it embarked on a mission to target certain groups because of their beliefs. She was in charge.
Construing all the events that we now know occurred in the light most favorable to Lerner, at the very least she is guilty of terrible management and non-existent oversight. Given Jay Sekulow's evidence that she herself sent harassing letters to conservatives, there is even more reason that American taxpayers should not be paying her salary as she sits home on "administrative leave." Heck, even Democrat Elijah Cummings thinks she should be terminated. So what is President Obama waiting for?
This is our government, people. Federal employees like Lerner work for us. At the very least, she abused her position by allowing this targeting to go on (through negligence or worse) and failing to inform Congress (and possibly some of her superiors) about it.
If the laws governing the firing of federal employees do not permit Lerner to be terminated immediately in circumstances like these, then there's a big, ripe reform issue for any politician with the initiative to seize it.