Pavlo Branko is a 35 year old, 12 year veteran police officer in Anytown, PA. One day, while on the job and on patrol, he severely injured his back and right knee. As a result of two surgeries, his medical records indicate he should permanently avoid strenuous activity, including sports and prolonged standing and running. He was reassigned to police desk work, processing arrests and other light duty. After almost three years, due to advances in digital technology, he was reassigned to be a clerk in the county courtroom. His performance ratings were above average in both job positions.

After only a year in the court clerk position, he was terminated based on the belief that he could not "perform the essential functions of a clerk." Assume both the ADA and Pennsylvania law state that discriminatory intent is shown "by evidence that an actual or perceived disability was a substantial motivating factor or reason for an employer's adverse action and the action is not required to be motivated by animosity or ill will."

In a claim against the employer, will Branko be successful in proving that his disability was a "substantial motivating factor or reason" for his termination? Explain fully. Use the language of the law in answering the question.

Please explain it as much as possible