"On July 2, 1863, his blundering nearly ended the United States." [referring to his contribution to the Battle of Gettysburg, as he was a Major General]
"Sickles’s greatest previous achievement had been fatally shooting his wife’s lover across the street from the White House and getting himself elected to Congress. Even his most fervent admirers could not have imagined that one day, far in the future, another incompetent New York politician, a president, would lay claim to that legacy by saying he could shoot someone on Fifth Avenue and get away with it."
What isn't mentioned there is that Sickles got away with the blundering on the battlefield too. He received a Congressional Medal of Honor for that stating (1) that he:
"Displayed most conspicuous gallantry on the field vigorously contesting the advance of the enemy and continuing to encourage his troops after being himself severely wounded."
From the article we all respond to, we know that: "Sickles himself was carried from the field on a stretcher, smoking a cheroot so that his men could see that he was still alive (they must have been overjoyed), though without most of his right leg."
1) http://www.cmohs.org/recipient-detail/1244/sickles-daniel-e.... "Place / Date: At Gettysburg, Pa., 2 July 1863 SICKLES, DANIEL E."