As the widespread effort to save the life of Georgia Death Row inmate Troy Davis reaches its final few hours, an unlikely assortment of celebrities have spoken out in support of Davis, who many say was unfairly railroaded on a capital murder charge with shaky evidence. But in the Twitterverse, Davis's relatively newfound celebrity has led to a strange phenomenon: Hundreds and hundreds of comparisons to Casey Anthony.

Atlanta rapper Big Boi and writer Salman Rushdie have joined in with ex-president Jimmy CarterRepublican Georgia Rep. Bob Barr, and former FBI director William S. Sessions in calling for clemency for Davis. On his brand new Twitter feed, Rushdie wrote, "As an Honorary Citizen of the State of Georgia and Professor at Emory University, I appeal to #georgiagov not to execute #Troy Davis." Big Boi, of the group Outkast, gave a lengthy interview to Global Grind, in which he said Davis had asked him to spread word about his case. He compared Davis's case to that ofAnthony, the Florida woman acquitted in August of killing her infant daughter. "Look at Casey Anthony in Florida. With way more evidence than what Troy has against him, they let her go scotch free," he told Global Grind. Journalist Goldie Taylor also made the comparison on Twitter. A search for "Casey Anthony, Troy Davis" on Wednesday returned hundreds of tweets every hour comparing the two cases. "They let Casey Anthony the child killer go but trying to kill Troy Davis ! boy boy boy racism is still alive & well," wrote T_eLizabeth, one of many, many Twitter users making the same point.

The similarity is there on the surface -- both high-profile cases have been protrayed as miscarriages of justice, Anthony's because it seemed she should be convicted and Davis's because of the questionable evidence against him -- but they're not really the same. The key difference is that Davis's 20-year saga has long been seen as an example of institutional racism, while Anthony's case was simply a surprising verdict.

The Los Angeles Times recalled the racial undertones in the Davis case on Wednesday: "Race has been a factor in the mobilization to save Davis, an African American whose purported victim was white. Davis' supporters think the Savannah police engaged in a frenzied rush to judgment after [Mark] MacPhail's slaying, coercing African American witnesses to testify against Davis." Raphael Warnock, the pastor at Atlanta's Ebenezer Baptist Church, said at a rally: "This is Jim Crow in a new era. There's just too much doubt for this execution to continue."

But Casey Anthony's case was never about race, except for the notion that, had she been a black woman, she wouldn't have been acquitted. The crime itself, though, and the trial that enthralled cable news over the summer, had no racial element. Anthony was accused of killing her own daughter, and acquitted of murder when the largely circumstantial evidence against her gave rise to reasonable doubt. The comparison to Davis is convenient, yes; effective in illustrating a sense of injustice, yes. But when you sit down to unpack it? We're not sure it's as water-tight as tweeters think.