WASHINGTON (MarketWatch) — Could the tragic shootings in Tucson finish Sarah Palin’s political career?

Her popularity was already in decline, according to polls preceding last Saturday’s attempted assassination of Democratic congresswoman Gabrielle Giffords. Palin’s “price” on InTrade’s exchange reflecting the odds of her getting the Republican presidential nomination in 2012 plunged to 12 immediately after the shootings from above 20 in December and 25 last summer, and it has remained there.

The now-infamous crosshairs displayed over Giffords’s district on the SarahPAC website have made Palin the poster child, some say unjustly, for the overheated political rhetoric that many feel led to the shootings at a Safeway grocery store in Tucson, Ariz.

Palin rejects Tucson criticism

Let’s make no mistake about it. The attempts by conservative spin doctors, and some temporizing liberal commentators, to portray this as “just” another deranged gunman in another senseless but unavoidable shooting don’t wash.

The target was a Democratic congresswoman at a constituent event, not some random victim in a shopping center. This was a planned assassination, not a moment of unreasoning fury.

There are strong indications that the suspected killer, Jared Loughner, is mentally unstable and has no coherent political philosophy. But the fact remains this was not a random shooting.

That Giffords has miraculously survived while six others were killed because they were at the wrong place at the wrong time — making the aftermath a familiar exercise in mourning for victims of senseless violence — does not change that fact.

The alleged killer did not target just any politician, but a Democrat who voted in favor of health-care reform, in favor of financial regulation and in favor of cap-and-trade legislation. She also opposed Arizona’s draconian anti-immigration law.

And she was one of 20 politicians in Sarah Palin’s crosshairs for removal from office. It doesn’t matter whether there’s any evidence that Loughner ever saw the Palin Web page with the U.S. map painting targets over offending districts. The map is symptomatic of a climate of political intolerance that afflicts the entire nation and is intense in Arizona.

That’s why Pima County Sheriff Clarence Dupnik — who, unlike the cable TV talking heads or Beltway pundits, was actually on the ground in Arizona — immediately made the connection when he blamed political rhetoric for the tragedy.

“I think it’s the vitriolic rhetoric that we hear day in and day out from people in the radio business and some people in the TV business, and what we see on TV and how our youngsters are being raised,” the sheriff said at a press conference within hours of the shootings. “I think it’s time as a country that we need to do a little soul searching.”

Palin has been singled out, not just because of the crosshairs image, but because she has systematically skirted what is acceptable in American politics, rallying her supporters with coded messages that often raised concern even during the 2008 presidential campaign. She has exploited a subtext of violence (“Don’t retreat, instead — RELOAD,” she famously tweeted) throughout her short-lived career on the national political stage.

Obama calls for unity

The danger, as Giffords and many others noted, was always that this inflamed rhetoric would incite unbalanced individuals to dangerous actions. And to all appearances, that is exactly what happened.

Palin has proven amazingly resilient when under attack, but this will be her biggest test yet. Her video statement in reaction to the shootings hit the right notes and, typically, blamed the media for manufacturing a “blood libel.” Time will tell whether this controversy puts an end to her political aspirations. See Palin’s Facebook page for her full statement.

It is a miracle that Giffords has survived, and it would be marvelous if she makes a full recovery and returns to Washington. We can only mourn the six people killed, and hope for the best for the other victims of this attack.

Predictably enough, Sheriff Dupnik was immediately pilloried by the right for his common-sense conclusions. It’s probably too much to hope that the country will heed his call for soul searching.