According to scholars, as living things evolved they developed deeply entrenched characteristics to avoid becoming victims and to succeed as predators. This impulse to deceive enables survival, and those that are unable to fool their predators or their victims die, leaving survivors without any sense that deceptive behavior is wrong—except among human beings.

Humans alone have developed ethical codes of “right” behavior that prohibit “a lying tongue.” From the Ten Commandments to common law, we decry deceptive practices and perjury, and severely punish transgressors—except politicians.

The 2012 presidential election race has by many accounts witnessed an unprecedented number of brazen lies. We should be asking why? In most cultures there is a social contract that creates a shared self-interest in the truth. We don’t want others deceiving us, so we agree not to deceive them.

So why do candidates and their staffs think they can lie? Is it because our evolved nature instinctively drives us to cheat—because we can’t help ourselves?

Is it because slinging mud at an opponent produces votes—and takes time and campaign dollars to wash clean?

Is this why we cry “foul” when opponents lie about our candidates, while crafting commercials that lie about theirs?

Americans rightly believe that transparent rule under codified law produces a fair opportunity for all to participate—a principle at the core of our competitive strength and our creativity.

Yet if we tolerate deception and fraud by our leaders, the ability to pursue life, liberty and happiness is sorely tested, as is our right to free speech, which itself depends on truthfulness.

Whether on the political left or the right, we are impelled by our history and our future to object vigorously to lies and deception.

We’ll have to employ solid judgment to distinguish between legitimate differences of opinion and outright dishonesty, but until we protest behavior that cynically insults our intelligence, we’re doomed to watch the sleaze worsen.

But then that’s the reason we have the right and the duty to vote.