Civil War Era Studies Professor Allen Guelzo was interviewed in a November 19 Huffington Post article about the recent Lincoln film.
From the Huffington Post:
President Lincoln accepted very few speaking commitments, notes historian Allen C. Guelzo, in a recent interview at his office at Gettysburg College where he serves as Director of Civil War Era Studies. To travel outside Washington to address a group required a major investment of time away from the Capitol for a president in the mid-19th century. (Compare that with President Obama's unrelenting travel schedule.)
When President Lincoln accepted an invitation to provide a "few dedicatory remarks" at Gettysburg, he clearly very much wanted to come.
According to Guelzo who has authored several books on Lincoln including Lincoln's Emancipation Proclamation and a forthcoming book, Gettysburg: The Last Invasion (Knopf, 2013), Lincoln had been mulling over when and how he could present to the American people a statement on the larger significance of the conflict and to explain why the enormous sacrifices were necessary.
Lincoln saw Gettysburg as the perfect opportunity for his statement. The 272 words he ultimately presented as the Gettysburg Address had been percolating in his mind for some time.
The morning of his departure, however, Lincoln had to reaffirm his commitment to attend. Son Tad, age 10, had awakened and was too ill to eat breakfast. Since an older son, Willie, had died just over a year ago, this greatly upset wife Mary, and she begged Lincoln not to leave her. The President, however, was fully committed to seize what he saw as an important opportunity to speak to Americans.