Sarah Palin has a special responsibility and opportunity in the wake of the attempted assassination of Rep. Gabrielle Giffords. For it was Sarah Palin and Sarah Palin alone who earlier put the crosshairs of a gun on Rep. Giffords. And so far, Palin's response has been Facebook prayers for the victims and an official denial that her widely distributed map involved gun sights at all. This is obscene duplicity at best.

Let us be clear. We do not know why the shooter targeted Rep. Giffords. Sarah Palin did not arm him or pull the trigger. We do not know if the shooter admired, loathed or ignored Sarah Palin. We will eventually know, and that will be a different accounting.

But only Sarah Palin put 20 Democratic members of Congress in her crosshairs, and only Sarah Palin bragged that 18 are now gone, leaving Rep. Giffords and Rep. Nick Rahall of West Virginia.

Someone has to say it. There has been an astonishing acceleration of violent right wing rhetoric. At the same time, the mainstream media has come to accept armed revolution (second amendment remedies) and violence as legitimate political discourse instead of calling it out as behavior that crosses a very dangerous line. In the past week alone, incendiary devices were received at the offices of the Democratic Secretary of Homeland Security and the Democratic Governor of Maryland.

This is what Sarah Palin and others like her have wrought with their violent and vitriolic rhetoric that literally places gun sights on people who don't agree with their extreme views.

Apologists on the right are already saying that while tragic, this event was simply the result of an isolated act by a deranged individual. There have always been deranged individuals. But they have not always had easy access to guns nor have they always lived in a 24-hour-a-day media machine that promotes a toxic soup of violent attacks on political opponents.

We are heartbroken by these events and our hopes and prayers are with the victims and their families. But prayers and broken hearts are not enough.

How can anyone not be haunted by the prophetic words of Rep. Giffords herself in March 2010, after her office was vandalized, threats received, and her name and district identified by Sarah Palin in her infamous crosshairs:

"Sarah Palin has the crosshairs of a gun sight over our district and when people do that, they've gotta realize there are consequences to that action."

Will there be consequences?

Imagine the consequences if Palin were to apologize for her use of targeting imagery, pledge never to demonize her opponents in such a way again, call on all of her passionate followers to pledge to do the same, and promise that she will call out those in the media who do not follow her lead.

Will Sarah do more than offer her condolences? She might sell fewer books and have fewer Facebook fans. But the consequences would be enormous.

Tell Sarah Palin: Renounce use of shooting images in political rhetoric immediately, and stop using your platform to promote and validate violent calls to action on the right. Click here to automatically sign the petition.

What happened in Arizona was not an isolated incident, but rather the culmination of a long stream of threats and attacks, most in response to the Congresswoman's support for health care reform.

In November of 2009, a staffer fearing for Rep. Giffords' safety called authorities after a visitor dropped a handgun during another "Congress on your Corner" event at a local Safeway in her district.2

And on March 22, 2010, just hours after Rep. Giffords cast her vote in favor of health care reform, a vandal jumped a gate and smashed the glass front door of her Arizona office.3

It was just days later that the now infamous map featuring Rep. Giffords' district in the crosshairs was posted by Sarah Palin's PAC. In announcing the map, Palin issued a chilling tweet urging her supporters "Don't retreat. Instead — reload!" Incredulously, through a spokesperson, Sarah Palin is denying that the crosshairs on her map targeting 20 Democrats who voted against health care reform represents gun sights.

As if the crosshairs weren't clear enough, Jesse Kelley, Rep. Giffords' Republican opponent in a hard fought race for reelection held an event two months later that makes the stakes all too clear. He asked supporters to donate $50 in order to "shoot a fully automatic M16" to "get on target" and help "remove Gabrielle Giffords." Sarah Palin subsequently praised Jesse Kelly on Fox Business News saying: "I don't feel worthy to lace his combat boots."

We agree with Keith Olbermann who said last night that "Violence, or the threat of violence, has no place in our democracy."

Our hearts are heavy for the victims of this tragedy. We must put a stop to the escalating hate rhetoric of the right and its very specific calls to armed violent action. Lines of decency have been crossed.