There were a number of candidates, and one was chosen by the head of the Executive branch. The Senate then gets to approve or deny the choice. This is all in the Constitution.

If I recall correctly, the bar used to be 60% for approval, by gentleman's agreement. A few years ago, the Democrats decided to discard that agreement (executing the so-called "nuclear option"). Now they're paying the price.

Ultimately the electorate will judge what was done. At the moment, it appears that they're leaning against the Democrats' strategy, but we'll know more after the mid-term results are in.