As he has frequently done in the past, President-Elect Obama invoked the spirit of Abraham Lincoln during his speech tonight. “As Lincoln said to a nation far more divided than ours, we are not enemies but friends,” Obama said. “Though passion may have strained, it must not break our bonds of affection.”

As Obama spoke those words, I couldn’t help but take another glimpse as the red state/blue state map posted on CNN.com. A swath of blue swept down from the northeast, across Pennsylvania and Ohio, following the course of the Ohio River to the Mississippi. In the trans-Mississippi region, Minnesota and Iowa were also blue, as were California, Washington, and Oregon.

A map of the United States in 1861 would’ve looked nearly identical. And it was that very time period when our nation was “far more divided.”

Tonight’s map has some significant differences compared to the 1861 map. Virginia, the capital of the Confederacy, is perhaps the most notable. There’s no way that would’ve been a blue state in 1861. Virginia was as gray as gray could get. Florida, Colorado, and New Mexico were also blue tonight. Florida was gray in 1861, and New Mexico was grayish. Colorado wasn’t much of anything.

Our states then were blue and gray, just as we characterize them today as blue and red. Obama tried to smash that media-contrived paradigm tonight. “Americans…sent a message to the world that we have never been just a collection of individuals or a collection of red states and blue states,” he said. “We are, and always will be, the United States of America.”

But make no mistake: As optimistic as I am about the tone Obama struck in his speech, a look at the map shows that we are unmistakably divided. A look at the popular vote shows only a 4.3-million-vote difference between the two men out of some 103 million votes cast (and that’s with votes from four battleground states still not finalized). That’s not as close as, say, Nixon/Kennedy or Bush/Gore, but close enough that Obama can’t legitimately claim a huge mandate.

I don’t mean to be a party-pooper. Even though we are divided, Obama is absolutely right: We are not as divided as we once were. While emotions ran high during the campaign, we are not at war with ourselves.

In fact, we now have an opportunity to look beyond the blue and red and make peace with ourselves. We have the opportunity to rise to another Lincolnesque ideal and call upon the better angels of our own natures and find our common ground.