I have to admit that I was unaware that Abe Lincoln sorta almost had a duel in the 1840s. I'm still wondering, from reading this article why the HELL California got rid of their law, back in1994, prohibiting duels. I would suspect it has to do with redundancy, and that gun fights over insults are still considered illegal in sunny CA.
In point of historic fact, the frequency of gun fights in the old west was quite low, and the occurrence of bushwhacking, ambush, and shooting folks from cover or from behind was more the norm. And as so often appears in articles documenting the Darwin Awards, alcohol was usually involved. Two things which lower the impulse controls in the human brain, especially the male brain - guns, and alcohol.
But then I'm still waiting for Greg Camp to provide all those historic examples of cross drawing from one's belt or holsters with the flap cut off, that I am middling certain don't exist anywhere. Greg gets his history from fantasy movies. I will agree that back in the single shot ball and black powder days combatants, especially pirates, were known for carrying spare weapons in their belts and bandoliers, but that could hardly be considered typical behavior.
I invite our readers to enjoy the following excerpt from wikipedia on dueling/ gun fighting, specific to the U.S.:
Several states have very high-level bans laid against duelling, with stiff penalties for violation. Several United States state constitutions ban the practice, the most common penalty being disenfranchisement or disqualification from all offices.
State constitutions prohibiting dueling specifically are those of Alabama, Arkansas, Florida, Iowa, Kentucky, Mississippi, Oregon, South Carolina, Tennessee, West Virginia and the Session law of Texas.
 State and territorial laws prohibiting duelling20 states, along with the District of Columbia and Puerto Rico, have some statute(s) (including constitutional provisions) specifically prohibiting duelling. The remaining 30 states either have no such statute or constitutional provision, or limit their duelling prohibition to members of their state national guard. This does not necessarily mean, however, that duelling is legal in any state, as assault and murder laws can apply.
States which specifically prohibit members of the state national guard from duelling are Arizona, Arkansas, Connecticut, Georgia, Iowa, Kansas, Missouri, Hawaii, Ohio, Oregon, Pennsylvania, Washington and New York.
States and territories which have statutory prohibitions on duelling for all citizens are Colorado, District of Columbia, Idaho, Kentucky, Massachusetts, Michigan, Mississippi, Nevada, New Mexico, New York, North Dakota, Oklahoma, Puerto Rico, Rhode Island and Utah. California previously prohibited duelling, but this was repealed in 1994.
Virginia passed the Anti-Dueling Act in 1810, creating civil and criminal penalties for the most usual causes of duelling, rather than for the act itself. It is still on the books. Virginia Code §8.01-45 creates a Civil Action for insulting words. Virginia Code §18.2-416 makes it a crime to use abusive language to another under circumstances reasonably calculated to provoke a breach of the peace. Virginia Code §18.2-417 makes certain slander and libel a crime.