Do I detect a hint of Coolidge? Every allusion in Obama's second inaugural (interactive)

Chris Wilson
Yahoo! NewsJanuary 25, 2013

By Chris Wilson

President Barack Obama is a highly literary orator. His prepared remarks often mimic the lofty prose of Abraham Lincoln, John F. Kennedy and Franklin Roosevelt, among many others, sometimes explicitly and sometimes with a few choice phrases that only seasoned pols would recognize.

Early in his second inaugural address, for example, Obama said this:

For history tells us that while these truths may be self-evident, they have never been self-executing; that while freedom is a gift from God, it must be secured by His people here on Earth.

One needn’t reach too far to see a clear echo in that line to the final clause of Kennedy’s inaugural:

...let us go forth to lead the land we love, asking His blessing and His help, but knowing that here on earth God's work must truly be our own.

Four lines later, Obama offers this history lesson:

Through blood drawn by lash and blood drawn by sword, we learned that no union founded on the principles of liberty and equality could survive half-slave and half-free.

Which is, without question, a nod to Lincoln’s famous second inaugural (as well as to Lincoln's "House Divided" speech):

Yet, if God wills that it continue until all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said "the judgments of the Lord are true and righteous altogether."

(Before his first inauguration, Obama reportedly took his family to the Lincoln Memorial, where he might have noticed that line inscribed in stone.)

Obama's affinity for Lincoln is well-documented. More surprising is the echo between this line from Monday's speech:

You and I, as citizens, have the obligation to shape the debates of our time -- not only with the votes we cast, but with the voices we lift in defense of our most ancient values and enduring ideals.

And this one:

It is the American story--a story of flawed and fallible people, united across the generations by grand and enduring ideals.

The latter was uttered in 2001 by President George W. Bush, the man Obama unofficially campaigned against in 2008.

The dustiest political science professor could not identify every allusion in a speech, made consciously or through the long seep of phraseology from one president to another. To round up the stragglers, I wrote a program to compare each sentence of Obama’s second inaugural to every sentence in every previous inaugural address. While the president surely draws inspiration from a wider body of sources, this was a good place to start.

In the following interactive, you can click any line to see matching phrases from past inaugurals.

This is not a triumph of artificial intelligence. Linguists and computer scientists have developed a range of strategies for measuring the similarity between sentences, going so far as to compare the synonyms for all nouns and all verbs in a sentence--a strategy some search engines employ to find relevant web pages for a query. For now, my strategy relies on a crude "bag of words" approach, which matches sentences based on the similarity of words, weighted to uncommon words. This is why you'll see some matches that only vaguely resemble one another. While I’ll be continuing to refine the code on future texts, for this first attempt it’s pretty literal. But how else will you uncover the affinity between Barack Obama and James Polk?