Haley made an endorsement mistake.
Sarah made an endorsement mistake.
Newt made an endorsement mistake.
Rick made an endorsement mistake.
Do we throw all of them out?
Of course not.
If, by that, do you mean her endorsement of Senator John McCain in 2010? Can you imagine what the press and the Democrats would have done if she hadn't endorsed the man who picked her out of 320 million individuals to be the potential vice president of the United States of America? People value loyalty, as they should.
Oftentimes endorsements reflect who the endorser considers the best option in a given situation.