Cokie Roberts, who drew on her upbringing in a powerful political family to fashion a career as a leading Washington journalist for NPR and ABC News, bringing a tough, knowledgeable voice to the rough-and-tumble political arena at a time when few women had national profiles in the news business, died on Tuesday in Washington. She was 75.

ABC News, in a posting on its website, said the cause was breast cancer.

Ms. Roberts was known to millions for both her reporting and her commentaries, moving easily among radio, television and print to explain the impact of world events and the intricacies of policy debates. And in books like “Ladies of Liberty: The Women Who Shaped Our Nation” (2008) and “Capital Dames: The Civil War and the Women of Washington, 1848-1868” (2015) she highlighted the often overlooked role of women in history, especially political history.

“Cokie Roberts was a trailblazer,” Nancy Pelosi, the speaker of the House, said on Twitter, “who transformed the role of women in the newsroom & our history books as she told the stories of the unsung women who built our nation.”

Ms. Roberts, who joined NPR in the late 1970s and ABC News in 1988, carved out a career that served as an example to later generations of women in journalism.