In 1860, just as in 2016, Pennsylvania was both doubtful and necessary for Republican victory.
Hay to Lincoln: "I saw one of the delegates to that Convn the other day from the Southern part of Indiana and he Said that the Indiana delegation would will go for Abraham Lincoln on the first balot.
He said it was all a mistake about Indiana going for Bates.
It is ascertained that the Germans are opposed to Bates, and this fact being once fully understood, will lay him on the Shelf."
Not sure why "the Germans" mattered in Republican politics, since immigrants typically voted Democratic.
But "the Germans" in Missouri were strong abolitionists, helped prevent Missouri from seceding and may have felt their fellow Missourian, Edwin Bates, not strongly abolitionist enough to suit them.
Hay to Lincoln: "I was of opinion some time since, that as it was so all important to carry Penna. it would be pollicy for us to place a Pennsylvanian at the head of the ticket, but I am now fully of the opinion that the Strongest ticket we can get is Abraham Lincoln for President and Simon Cameron for Vice P. –"
Sadly, Pennsylvania has seldom produced Republican leaders worthy of its more conservative Republican voters.
Pennsylvania's Senator Cameron began as an anti-abolition Jackson-Van Buren Democrat but eventually switched to Republican supporting abolition.
He did poorly as Lincoln's Secretary of War but, indefatigable, later became a great power in Pennsylvania state politics.
Today the longest North-South road through Harrisburg is named Cameron Street.
Hay to Lincoln: "I must not close, without mentioning the fact that we have a little Abraham Lincoln at our house, about twenty four hours old– His arrival created something of a Stir... "
A google of Carson Dobbins Hay produces nothing about a son named Abraham Lincoln.
Maybe someone else's?