Washington (CNN) -- Wendy Davis is attacking her partially paralyzed Republican opponent Greg Abbott in the Texas governor's race -- with an ad that features an empty wheelchair.

"A tree fell on Greg Abbott. He sued and got millions. Since then, he's spent his career working against other victims," a narrator says of the wheelchair-bound Abbott.

The spot is a Hail Mary from the Democratic state senator who is badly trailing in the race. Abbott led Davis 54% to 40% in a recent CBS/New York Times/YouGov poll, and there are few signs she's likely to close that gap before the November 4 election.

The ad argues that Abbott successfully sued for his 1984 injury, but later as a Texas Supreme Court justice and state attorney general opposed similar efforts from other people suing hospitals and corporations.

"Abbott argued a woman whose leg was amputated was not disabled because she had an artificial limb," the narrator says. "He ruled against a rape victim who sued a corporation for failing to do a background check on a sexual predator. He sided with a hospital that failed to stop a dangerous surgeon who paralyzed patients."

Abbott's use of a wheelchair has been featured prominently in some of his own ads -- including a biographical spot where he says he rolled up a parking garage's ramps to strengthen his arm after a tree fell on him in 1984, leaving him partially paralyzed. In another, he says, "a guy in a wheelchair can move faster than traffic on some roads in Texas" as he touts a transportation funding plan.

Abbott spokeswoman Amelia Chasse blasted the Davis ad, saying it "completely disqualifies" Davis -- hinting that it could hurt her in future campaigns, too.

"It is challenging to find language strong enough to condemn Sen. Davis' disgusting television ad, which represents a historic low for someone seeking to represent Texans," she said. "Sen. Davis' ad shows a disturbing lack of judgment from a desperate politician, and completely disqualifies her from seeking higher office in Texas."

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