[BroJoeK]

"Well played has become a cliche, but wow, was this convention well played by Lincoln and his team."

Interesting to notice that both Democrats and Republicans rejected their leading "establishment" candidate, as too radical on slavery & so unacceptable to Southerners.

But Democrats required 2/3 to win and Douglas maxed out at 60% -- Charleston produced no nominee.
Republicans in Chicago also rejected their leading establishment candidate, Seward, as too radical on slavery, but Republicans only required 50% to win, and did not expect any Republican to appeal to Deep South voters -- they only hoped to win some Northern Democrat & Border State votes.
And for that, somehow, "rail-splitter" Lincoln fit the bill.

And, as Catton reports, there were the words of Kentucky's Cassius Clay:

"Gentlemen, we are on the brink of a great civil war...
You must give us a leader at this time who will inspire our confidence and our courage.
We must have such a leader or we are lost.
We want you to name Abraham Lincoln.
He was born among us and we believe understands us."

[colorado tanker]

I think even if Douglas had been nominated at Charleston it was inevitable the Southern Democrats would nominate their own candidate in light of their demand for a territorial slave code and Douglas’ steadfast opposition to one.