Maya Rockeymoore Cummings, the widow of the late Rep. Elijah E. Cummings, is running for the Democratic nomination to replace him in Maryland’s 7th District.

Rockeymoore Cummings resigned Monday night as chairwoman of the Maryland Democratic Party before announcing her candidacy on MSNBC ahead of a formal campaign kickoff Tuesday in Baltimore. Elijah Cummings was chairman of the Oversight and Reform Committee when he died last month.

“I fought right alongside Elijah for the last 12 years, and we knew each other another 10 years before that,” Rockeymoore Cummings told MSNBC’s Rachel Maddow. “So I’ve been on this path, fighting for the soul of our democracy, fighting for health care, for education and for a better America for all. And so he wanted me to continue this fight.”

Her campaign for the heavily Democratic seat, which is holding its special election primary on Feb. 4, sets up a battle with former Rep. Kweisi Mfume, who preceded Cummings in Congress before stepping down to become chairman of the NAACP in 1996. The former congressman announced his candidacy last week.

Rockeymoore Cummings said Monday that she and her late husband had discussed her taking his seat as early as six months ago, when he was ill.

Rockeymoore Cummings told Maddow she’s planning to have a preventative double mastectomy on Friday — a procedure that was scheduled before her husband died. Her mother died from breast cancer in 2015, and her sister was diagnosed with the disease last year. Rockeymoore Cummings said the recovery will take two to four weeks.

“I will be laser-focused on making sure that I am active, making sure that my campaign is strong, that I’m doing everything that I can to fundraise, and, of course, focus on social media and the things I can do to have a presence even while I’m not physically able to be out in the community,” she said. 

Should she win, Rockeymoore Cummings would become the 47th widow elected or appointed to Congress following the death of a spouse, according to the House Historian’s Office. The total does not include Leonor K. Sullivan, a Democrat from Missouri, who did not succeed her husband directly. She lost a special election primary but won the subsequent general election for the seat, according to Rutgers’ Center for American Women and Politics.

Only one current member of Congress, California Democratic Rep. Doris Matsui, is a widow who succeeded her spouse, Robert T. Matsui after he died in 2005, shortly after winning a 14th term. 

Rockeymoore Cummings briefly ran for governor of Maryland last cycle and was elected state party chairwoman in December. The founder of consulting firm Global Policy Solutions, she was previously a senior resident scholar at the National Urban League. She has Hill experience, too, having served as vice president of research and programs at the Congressional Black Caucus Foundation and as chief of staff to former New York Democratic Rep. Charles B. Rangel. She also served as an aide on the House Ways and Means Committee.

Hillary Clinton carried Maryland’s 7th District by 53 points in 2016, so the main competition for the Baltimore-area seat will come in the Democratic primary. Rockeymoore Cummings was the big name many potential candidates were waiting on, but others could still enter the race ahead of the Nov. 20 filing deadline. The special general election will be on April 28, the same day as the state’s regularly scheduled primaries. Another general election for the next two-year term will be held in November 2020.

For Rockeymoore Cummings, winning her husband’s seat would end a streak for Maryland, which has not had a woman in Congress since Sen. Barbara A. Mikulski and Rep. Donna Edwards left in 2017.

Paul V. Fontelo contributed to this report.