I could freely give my life to save his. Virginia C.

[Steve]

I found out what happened with Private Clifton. Apparently the review of his court-martial by President Lincoln didn't go particularly well. While the letter from his daughter Virginia may have stopped him from being executed, he was sent to Ft Jefferson in Florida by May 2, 1864. He wasn't released until July 3, 1865, three weeks before Samuel Mudd and the others arrived.

After being dishonorably discharged he went back to New Jersey with his wife Hannah and kids and worked in the construction/building trade. He died on September 12, 1901 in Ocean City, New Jersey at around age 75. His widow, Hannah tried to apply for a widow's pension but, predictably, was denied.

His oldest daughter Virginia, who wrote to President Lincoln pleading for his life, married a Samuel Armpriester in 1869. She would've been 16 in January 1864. According to unsourced family trees on Ancestry.com, which I haven't been able to verify, she died a year after her father, in 1902 in her mid-50's.