Auto-Pen Signatures of Bills  I blogged about this in 2011,
citing to an Office of Legal Counsel opinion that concluded:
[We find that, pursuant to] the legal understanding of the word
“sign” at the time the Constitution was drafted and ratified and
during the early years of the Republic …, a person may sign a
document by directing that his signature be affixed to it by
another. We then review opinions of the Attorney General and the
Department of Justice and find the same understanding reflected
in opinions addressing statutory signing requirements in a
variety of contexts. Reading the constitutional text in light of
this established legal understanding, we conclude that the
President need not personally perform the physical act of
affixing his signature to a bill to sign it within the meaning
of Article I, Section 7.  I haven’t followed this issue since,
but I thought I’d point to a contrary view from Prof. Terry
Turnipseed, which is in the news again because of the auto-pen
signature of the fiscal cliff b