If Debbie Dingell wins the campaign she’s formally launching on Friday — a solid if not quite certain bet — she’ll make history in more than the obvious way.  

She would be keeping one House seat in the same family well into a ninth decade, but would also become the first person to ever come to Congress as the successor to a living spouse.  

That might sound like an amazing distinction to modern ears, given how control over accounting firms, law offices, medical practices and other small businesses now pass relatively routinely to the younger half of a married couple when the older person (usually the husband) tires of the daily grind. And in Washington, D.C., of course, the dominant political story is whether Hillary Rodham Clinton will end up getting the same government job her husband had for eight years.  

But congressional political dynamics have proved remarkably resistant to this sort of evolution in family and gender roles. John D. Dingell — who won his job in 1955 when his father, a fellow Michigan Democrat and his namesake, died during his 12th term — is one of eight House members and joins one senator (Alaska Republican Lisa Murkowski) in the ranks of lawmakers who replaced their dads in Congress. Ten other House members and three other senators had fathers who were members. And Indiana Democrat André Carson won the seat left open in 2008 when his grandmother Julia died.  

But, until now, waiting for her husband to die in office has been the only way for a woman to benefit from family connections in launching her own congressional career. This “widow’s mandate ” has proved remarkably resilient: Nearly 1 in 6 of all the women who have ever been in Congress — 38 House members and eight senators — arrived as the successors to their deceased partners.  

For much of the 20th century, they were virtually the only women in Congress, and they rarely stayed long. Elected or appointed as sentimental and convenient placeholders, they generally agreed to return home without a fuss as soon as the party bosses settled on a more “suitable” (and male) long-term successor.  

That pattern has faded a bit. Just two women in the 113th Congress hold seats that opened up when their spouses died, and California Democrats Lois Capps and Doris Matsui are both House members with considerable clout and staying power in their own right.  

On the roster of 298 women who have ever been members, though, there’s not one who won an election to succeed a husband who retired or resigned. This is the particular glass ceiling that Debbie Dingell is well positioned to break.  

There was a time, in 2008, that it could have cracked. Prominent attorney Camille Andrews won the Democratic nod for the House seat in southern New Jersey that her husband, Robert E. Andrews, said he was giving up to run for the Senate. But after getting crushed in his primary challenge to incumbent Sen. Frank. R. Lautenberg, the congressman decided he wanted to keep his current job — and his wife acceded to his request by giving him her nomination.  

Elizabeth Dole won a single term in the Senate, where her husband, fellow Republican Bob Dole, stands as one of the modern-day giants. But her arrival in 2003 came more than six years after he resigned to run for president. And the western tip of her North Carolina district is 610 miles from the southeastern corner of his Kansas territory.  

No man has ever succeeded his wife in Congress. The most recent to be recruited to make such a move was Mark Kelly in 2012, when Democratic Rep. Gabrielle Giffords resigned a year after an attempted assassination in Arizona.  

The baton-passing between Mr. and Mrs. Dingell has the potential to lack any of the drama or political asterisks of those earlier near parallels.  

Debbie Dingell, 60, will enjoy nearly universal recognition and will have no trouble raising whatever money she needs — not only because of the surname she took when she married the congressman in 1981, but also because she long ago became a significant force in the political and advocacy worlds of Detroit and the Beltway.  

For 32 years, ending in 2009, she was an executive at General Motors, serving as vice chairwoman of the company’s philanthropic foundation and executive director for corporate public affairs and community relations. (A grandfather was among the founders of Fisher Body, a forerunner of GM.) She has long held one of Michigan’s seats on the Democratic National Committee and played key roles in both Al Gore’s and John Kerry’s successful efforts to carry the state. She is now in her final year as chairwoman of the board of Wayne State University in Detroit and is overseeing a manufacturing research project for the trade association representing the Big Three automakers.  

It was that résumé that prompted an effort last year to recruit her to run for the Senate seat from which fellow Democrat Carl Levin is retiring. There’s only one possible thing preventing her from being a slam dunk in the 12th District — a primary challenge from the left. The district twice voted for President Barack Obama by a 2-to-1 margin, and includes the college town of Ann Arbor. (The candidate getting the buzz on that front for a possible Aug. 5 primary challenge is state Sen. Rebekah Warren, who says she’s not yet made up her mind.)  

The 87-year-old Dingell did not seem concerned in talking to reporters after his Monday retirement speech. “The lovely Deborah,” as he almost always calls her, “will make a hell of a congressman, and she doesn’t need any advice from me.”