Mattis picks Muslim Brotherhood supporter to #3 position at Pentagon--she withdraws after White House opposition
Patterson was Obama's ambassador to Egypt. During that time a presidential candidate--Morsi-- supported by an organization called the Muslim Brotherhood theoretically won an election, and began imposing strict sharia law on Egyptians. Most Egyptians were strongly opposed to this, and the result was a military coup which deposed Morsi.
According to Egyptian "reformers," Patterson supported the Muslim Brotherhood.
State has always been pro-Islamist, and it's hard to imagine that Patterson could have had a 30-year career at State--culminating in being named ambassador to Egypt--without having verified her support for that philosophy. Similarly, it seems unlikely Obama would have named her to that post unless he knew her position.
All this is commonly known. But the bottom line is...unsettling: Mattis didn't pick Patterson's name out of a hat. Either he knew quite a bit about her, or else one of his advisors put her name forward. Either way, it doesn't look good for Mattis. Either he's not all that savvy, or else he has some snakes in his advisor positions.
Bad either way.