Entering the White House as a junior speechwriter, Keenan remembers being immediately awed by the significance of the office he served and quickly learning the weight of responsibility that's placed in a president called on to console a nation.
"When you come in here as a speechwriter...you have big visions of State of the Union addresses, and commencements and moonshots and all sorts of great speeches. It never crosses your mind that you're going to have to write a bunch for tragedy," Keenan told David Axelrod on "The Axe Files," a podcast from the University of Chicago Institute of Politics and CNN.
"And it happened way too often," he said.
On his last day in the White House, Keenan paused to reflect on his journey that began as an intern on Obama's 2008 presidential campaign and ended with him serving as the President's chief speechwriter.
He also spoke about his close collaboration with the President, who Keenan is quick to credit as the true head speechwriter at the White House.
"I've learned along the way that [a speech] doesn't have to be perfect; it has to give him something he can work with and then he can work magic in about a tenth the time that you did," Keenan said, offering the speech memorializing the victims of the Charleston church shooting as an example of when President Obama's own writing elevated the address to another level.
"I pulled two all-nighters on that, and then in the span of five hours he crossed out the last two pages of the speech and rewrote them longhand in a way that I couldn't reach," Keenan recalled. "And it's frustrating that you can't get there but it's also just incredibly rewarding to see that he can."
One of Keenan's most memorable speeches from his White House tenure is one that he surely wishes he'd never written: the memorialization for the six victims of the 2011 Tucson shooting that targeted then-Congresswoman Gabrielle Giffords.
One of the victims was nine-year-old Christina-Taylor Green, who was born on September 11, 2001. Like other children born on that day, Green happened to be featured in a book Keenan's research aide discovered, in which her picture and others were placed next to experiences people wished for them to have in their lives. One of the wishes near Green's photo said, "I hope you jump in rain puddles."
"So I was reading this, and I think it was the morning of the speech," Keenan said. "I emailed myself while I was getting ready in the morning, saying, you know, 'If there are rain puddles in heaven, Christina's jumping in them today.' And then added that in" to the speech.
It is these personal stories, Keenan says, that give a speech life and resonate with an audience. He remembers drawing on his own personal stories when he came into the White House, as members of his own family experienced the pain of job loss and the anxiety brought on by financial hardship during the height of the recession.
"I channeled all of it, because you've got to figure whoever the President is talking to has those same concerns and fears, and they might have lost their job, they might be on the brink of losing their home," Keenan added. "And you've got to connect with them rather than just rattle off a list of bullet points on some policy or program."
Without hesitation, Keenan says that the White House is the greatest professional experience of his life. But he didn't learn the importance of people-focused politics scaling the heights of political speechwriting. Instead, he says, he learned his most valuable lesson in politics as a lowly aide opening mail in Ted Kennedy's Senate office.
"The most important thing I learned was in Kennedy's mailroom. And it was opening the mail and reading the mail, and seeing how important politics and public service were to people's lives," Keenan said. "That changed my entire outlook on public service."
To hear the whole conversation with Keenan, which also covered his next job helping the President to write his much-anticipated memoir, and more, click on http://podcast.cnn.com
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