Short answer? Back then, Honest Abe was a gangly state politician. Now, he's on not one but two forms of U.S. currency.

Long answer? Well, it'll take a quick sec.

The "House Divided" speech put Lincoln on the political map beyond Illinois. He had clearly collected a decent amount of support within the state, since the party nominated him, but the speech launched him onto the national stage. Speeches like this were printed in newspapers around the country and were read and reacted to much like major speeches are today. In fact, Lincoln delivered the speech to the printers himself. (Good call, Abe.)

It's probably that the Lincoln-Douglas Debates wouldn't have been the spectator sports they were without the fame Lincoln got from the "House Divided" speech. Douglas was well-known around the country, and already influential. Lincoln was a one-time congressman and had been out of Congress for years.

The speech reflected the fears of lots of northerners, who had always fought against the spread of slavery into their region. The Dred Scott decision was met with outrage in the North, and in combination with the Fugitive Slave Law of 1850 and the chaos of Bleeding Kansas, tensions were running high.

Obviously, Lincoln and his ideas weren't universally liked—after all, he lost the senatorial election. But his performance at the Republican Convention and the following debates put him in Republican's eye and set him up to be their presidential candidate in 1860.

By then, his fame had grown enough that he won…setting off the Civil War.

His biographer William Herndon, in his 1888 book, talks about how skeptical people were about the validity or wisdom of the "House Divided" speech when it was given. Like any strongly opinionated political speech, it was met with mixed reactions, especially since Lincoln went a bit conspiracy theory in parts. (Source)

The speech has never really fallen out of the American mindset, though. Lincoln became such a beloved president (except in some areas) that many of his speeches have remained important, well-known documents of American history.

Really, though, people have focused only on the first paragraph of the "House Divided" speech. All the specifics about the Kansas-Nebraska Act and the Dred Scott decision kind of get brushed aside. This is partly because they aren't as universal, or applicable to other moments in time. The Civil War has a special place in American memory and identity, and since the "House Divided" speech is closely tied to that conflict historically, the memory of it lives on as well.

That first paragraph—or at least a few key sentences—is recognizable by pretty much everyone who nerds out on U.S. History. President Obama even referenced it in his Second Inaugural Address in 2013.

And he didn't say, "This is from the House Divided speech"…because he didn't have to. Everyone listening knew what he was talking about.