Joni Ernst snapped years ago, overnight.
She came into office normal, confident, MIL strong and with purpose.
She decided to publicize an assault she suffered in the past, and has been permanently dazed and confused, complete with change in both appearance and countenance, a reliable head-nodding McConnell Stooge, ever since.
Very Curious Case of Joni Ernst.
She was beholding to the Romney Machine and apparently could not - or would not - break away. But your points are well taken, in that she doesn't even seem like the same person... merely another example showing that nothing which goes to DC ever changes for the better.