Was failed polygraph the reason she didn't get promoted?

After a workplace theft, an employee fails a polygraph test and then misses out on a promotion. Can she successfully sue? Read the dramatized version of this real-life case and see if you can determine the outcome.
“Why are we still dealing with this Marla Eders issue?” asked VP Adam Miller. “She resigned months ago.”
HR manager Lynn Rondo thumbed through a pile of paperwork. “Marla claims we failed to promote her to general manager because she failed that polygraph last year,” she said.
“Fill me in on what happened,” said Adam.
Far from a model employee
“There were only a handful of people with access to our cash deposits,” Lynn said. “When one went missing, we had three employees submit to a polygraph.
“Two passed and Marla failed,” she continued. “We could never prove that Marla did it, so we never took any action. But it certainly raised a trust issue with us.”
“That wasn’t the only issue we had with Marla, right?” asked Adam.
“No,” said Lynn, reaching into a filing cabinet and pulling out Marla’s file. “We’d disciplined her for everything from tardiness to safety violations.
“And after she cursed out a co-worker, we had to give her the choice to quit or let her go,” she added.
“And now Marla’s claiming we didn’t promote her because of the failed polygraph,” Adam said.
Marla went ahead with her lawsuit against Lynn’s firm.
Did the company win?
The decision
Yes, Lynn’s company won when the case was dismissed on summary judgment.
Marla claimed she was passed over for a promotion because she failed a polygraph test – even though a full investigation never proved she had anything to do with the missing cash deposits.
Lynn’s company admitted that the failed test raised an issue of trust.
But the judge ruled in the company’s favor for one reason: Marla’s long history of performance problems.
Marla’s many performance issues – with the paperwork to back up the company’s claims – made it clear she wasn’t the right fit for the position.
Analysis: A risky (but legal) tool
Polygraphing people to get to the bottom of suspected fraud is a bold move – and it may not be the right one for every company.
But polygraph tests are legal for private firms under certain circumstances, like when an employee is “reasonably suspected” of involvement in a workplace theft, embezzlement, etc., that resulted in specific economic loss to its employers – like the theft of the cash receipts did in this case.
Cite: Bass v. Wendy’s of Downtown, Inc. Fictionalized for dramatic effect.