WASHINGTON — As Tammy Duckworth sees it, her path to Congress began when she awoke in the fall of 2004 at Walter Reed Army Medical Center. She was missing both of her legs and faced the prospect of losing her right arm.

Months of agonizing therapy lay ahad. As the highest-ranking double amputee in the ward, Major Duckworth became the go-to person for soldiers complaining of substandard care and bureaucratic ambivalence.