In the pit of the Great Depression, with purple dust clouds and grasshopper swarms descending on parched South Dakota, two newlyweds stood at a crossroads in the 1930s.

Unable to afford tuition, Hubert Humphrey had dropped out of the University of Minnesota to help his father keep his pharmacy afloat in Huron, S.D. They'd often accept hogs and chickens for payment from cash-strapped customers.

His father needed him and paid him $15 a week. But Muriel Buck, whom Humphrey married in 1936, had higher hopes. She insisted her husband return to college to further his political aspirations.

"Fortunately, in the tug of war over my loyalty Muriel won," Humphrey wrote in his 1976 autobiography. He credited "the strength of her determination" — plus the $675 Muriel had saved as an electric company bookkeeper — for pushing them down the fork in life's road that would include stops as Minneapolis mayor, U.S. senator and vice president.

Nearly 40 years ago, in January 1978, Hubert Humphrey died and Gov. Rudy Perpich appointed Muriel to fill his seat for the next 10 months. Suddenly, she stepped out from the shadow of her "happy warrior" husband to become Minnesota's first female U.S. senator and the only woman in the chamber at the time.

"Half of what we credit Hubert for we should credit Muriel, because they were a team from beginning to end," former Vice President Walter Mondale said when Muriel died in 1998 at 86.

In an early interview in 1960, when Humphrey lost his first Democratic presidential run to John Kennedy, Muriel said: "I enjoy campaigning so much I think I should have my head examined. Hubert and I both get a lift out of meeting people."

She logged more than 650,000 miles campaigning for her husband over the years while raising their four children and shuttling between Washington, D.C., and Minnesota. She often sewed her own dresses and was an accomplished pianist and water-skier.

"My mother was a very practical, innovative and determined woman always engaged in the politics," their second child, former Minnesota attorney general Skip Humphrey, said in a recent interview. "She was a tough lady right there in the conversation ever since Mom played that key role in demanding Dad get back to the University of Minnesota if they were going to move forward."

Acknowledging that she was "probably a little more liberal than Hubert," Muriel's 10-month stay in the Senate was no mere caretaker stint. She introduced legislation to combat unemployment and genetic diseases in infants and supported mental health and food programs.

Skip Humphrey remembered one family vacation his mother sacrificed in the name of public service. As a board member on a Rockefeller family foundation, she'd been offered access to their sprawling ranch near the Grand Tetons in Wyoming in 1978.

"I got a call and she told me to get my family out there and she'd meet us in the Tetons," her son said. "Well, we waited and waited but she never made it. She was sleeping on a cot in the halls of Congress, waiting to vote on the Panama Canal treaty."

With one vote to spare, the treaty was approved. Panama won control of the canal, which would remain neutral.

Muriel toyed with running for the Senate beyond 1978 but decided against it out of her own health concerns and a potential DFL primary clash.

As Hubert battled bladder cancer that spread in the mid-1970s, Muriel had her gallbladder removed in 1977 and was hospitalized with exhaustion suffered while tending to her husband in his final days.

"If I had run, I think I would have won," she said. But "the last two years have been very hard on all of us, especially me."

Republican Dave Durenberger wound up beating businessman Bob Short in 1978, part of the so-called Minnesota Massacre that ousted DFLers from both U.S. Senate seats and the governor's office.

The next year, Muriel returned to South Dakota to dedicate an airport in Huron. She learned that childhood friend Max Brown, a retired Nebraska radio executive, had recently become a widower.

They wrote, met in Willmar, Minn., and were married in 1981 at her Excelsior home on Lake Minnetonka. Both were 68. "I think if you've had a good first marriage, you're likely to have a good second one, too," she said.

Splitting time between Excelsior and Sanibel Island, Fla., she stepped out of the limelight as Muriel Humphrey Brown.

"She had a different, but marvelous, life with Max, and she just loved Sanibel," Skip Humphrey said.

"My mother was quite a talented woman," he added, recalling how his father wanted to attend every embassy reception in Washington as a senator to learn more about international relations. "But she couldn't afford to buy all the dresses and hats she needed. When dinner was over at 6:30, we'd clear the table and out would come the dress patterns and she'd start cutting and sewing."

As second lady in 1965, she told a New York fashion reporter she "always had a suppressed desire" to enter one of her homemade dresses in a Vogue magazine contest, "but, for political reasons," she decided against it.

And for Muriel "Buck" Humphrey Brown, there were always political reasons to consider.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. A collection of his columns is available as the e-book "Frozen in History" at startribune.com/ebooks.