For months, Newt Gingrich has floated the same challenge to President Barack Obama that underdogs have hurled at their political rivals for more than a century: Let's debate. And not just once or twice, but many times, with no moderators to intervene or inhibit us.

Just two candidates, head-to-head, Lincoln-Douglas style.

As a Lincoln historian, I've studied the famous meetings between challenger Abraham Lincoln and incumbent Stephen Douglas that set the prairies on fire during the 1858 U.S. Senate race in Illinois.

Gingrich has even called me to discuss them. As I told him, the problem is that, as famous as those debates are, their reputation far outweighs their value. And they hardly are an inspiring model for modern candidates seeking to showcase their oratorical skills.

These lengthy rhetorical contests tested the endurance of the audiences and the candidates. Rather than inspiring memorable words, they proved for the most part an embarrassment.

The encounters were brutally sarcastic, featuring highly personal attacks rather than elevated discourse. And while they were the first major political forums transcribed by stenographers, the debates were not even accurately published.

The texts we know today were massaged by partisan editors eager to make their candidate sound less garbled. Newspapers of the era were openly connected to major parties -- imagine Fox or MSNBC editing debate tapes before broadcast.

Still, no friendly editing could disguise the debaters' shortcomings, including their open prejudice. Both men used the N-word -- a term that, even then, shocked some.

Douglas, who voiced horror at the sight of African American leader Frederick Douglass riding around town in a carriage driven by a white man, maintained that American democracy was created only "for the benefit of white men and their posterity forever."

While Lincoln insisted that the Declaration of Independence applied to all, he also descended into bigotry, acknowledging the "physical difference" between whites and blacks. In the fourth debate, he went further.

"I am not, nor ever have been, in favor of bringing about in any way the social and political equality of the white and black races," he declared in Charleston, Ill., to robust cheers, "nor ever have been in favor of making voters of the negroes, or jurors, or qualifying them to hold office, or having them to marry with white people."

It was not the future emancipator's finest hour.

To understand Lincoln-Douglas, we must remember a time when politics focused the frenzy that is today captured by the Super Bowl and "American Idol."

With little to entertain them outside church and county fairs, Americans flocked by the thousands to political events.

Spectators stood for hours, toted banners, hocked wares, fired cannons, downed hard drink and raucously interrupted speakers with hurrahs and harassment.

It was not uncommon for fistfights to break out in the farthest reaches of these large crowds, where the unamplified voices of the debaters seldom reached.

During one debate, a Republican smeared excrement on Douglas' carriage.

Such diversions helped audiences endure outdoor marathons at which the opening speaker held forth for an hour, the responder took 90 minutes, and the first debater topped off with a half-hour rejoinder, all unthinkable in today's sound-bite culture.

If Gingrich becomes the Republican presidential nominee and demands more than the usual number of debates, Obama should think twice about accepting. Like Douglas, he has much to lose and little to gain.

No one can really say who won the Lincoln-Douglas debates; though Douglas prevailed in the election, he made his opponent a star.

Widely reprinted in the national press, the debates proved such a phenomenon that Lincoln's name became a household word. Two years later he defeated Douglas for president without ever debating again.