During those times stressful campaigns, the heartbreaking losses, the teasing from the news media and other politicians about his failed candidacies Cook's wife, Camille, was by his side, shaking hands, making calls, passing out fliers and comforting the family.
She never liked politics, and her husband knew it. She did it for him. She never complained about lost family vacations, the draining of their personal wealth to help finance campaigns or the lack of privacy.
Now, he's there for her.
Camille Cook has Alzheimer's.
She was diagnosed in 2008, but the family believes the disease took hold about four years earlier. During the past two years, Cook says, aphasia has set in, making it nearly impossible for her to communicate.
"She has an acute sense of colors," he says. "She still enjoys the beauty of the mountains, of the flowers. She is happy most of the time."
Whether she recognizes those around her is hard to say, but Merrill says it's clear she senses the love.
Cook, whose passion for politics began when he was 8 years old, could just not stop running for office. But he has a new obsession as the full-time caregiver for his wife of nearly 45 years and he loves it.
He wakes her and gets her ready for the day. He cooks for her. He grooms her. He entertains her. He helps her to bed at night.
"It is by far the greatest thing I've ever done," Cook told me when I sat down with him, Camille and two of their five children recently at their home in Salt Lake City's upper Avenues.
"I've learned more things, had more satisfaction, had more sense of accomplishment taking care of my wife than anything I've done. That includes running a successful business and serving in Congress."
During a 10-year stretch while their kids were growing up, Cook lost six elections the state school board in 1984, Salt Lake City mayor in 1985, Salt Lake County Commission in 1986, governor in 1988, governor in 1992 and Congress in 1994.
He finally won an election to the 2nd Congressional District in 1996, although the Republican establishment didn't help him much.
Resentment remained over his previous quests as an independent for governor and Congress, when he challenged GOP candidates.
He was re-elected in 1998, but fell short in the Republican primary when he pursued a third term in 2000. He tried to win back his seat in 2002, but fizzled at the GOP convention.
Still, Cook was not done. He ran for Salt Lake County mayor in 2004 and for the U.S. Senate in 2010 against three-term incumbent Bob Bennett. He failed in the first round at the Republican State Convention.
He ran for county mayor again in 2012, and Camille often accompanied him to events, despite being deep in the throes of Alzheimer's.
Their story began in 1967, when Cook returned from his Mormon mission and resumed his studies at the University of Utah. They both had attended East High Merrill in the Class of '64, Camille in the Class of '65 but they didn't know each other there.
He took her to the old Heidelberg Restaurant in Farmington on their first date. They went back several times to that elegant establishment during the courtship.
While Merrill could name nearly every member of Congress and the margin of victory earned by each U.S. president, Camille's passion was music.
She majored in voice and French at the U., then studied opera at a college in Pittsburgh while the two were engaged.
"She sent me a picture of her being lifted in the air by a male cast member while they were rehearsing an opera," Merrill told me. "I got jealous. I got in my car and drove straight to Pennsylvania. I ran out of gas in the middle of the night in Wyoming. But I got there and sat in the front row during the rest of their rehearsals."
The couple married and moved to Boston, where Cook earned his MBA at Harvard. Camille supported the family during his graduate studies, working at a bank and as a research paper editor at Harvard. After his graduation, they remained in Boston while Cook worked at a financial-consulting firm.
They returned to Utah in 1974 and Cook eventually founded the Cook Slurry Co., an explosives manufacturer, with his father.
Meanwhile, as their family grew, Camille performed for the Utah Opera, the Salt Lake Opera and at many other venues, including church gatherings and funerals.
Pollster Dan Jones once told Merrill he would have better luck if he ran Camille for public office instead of himself.
"Everyone loved Camille," Cook said.
Now, with all five of their grown children enjoying successful careers outside of Utah two in California, one in Connecticut (where she works at Yale), one in Washington, D.C., and one in New Zealand Cook shoulders the task of caring for Camille.
He gets help from neighbors and fellow members of his Mormon ward, or congregation.
An old political ally, Greg Beesley, who worked with Cook on the front lines during the fight to get tax limits on the ballot in 1988, comes by to sit with Camille when Cook wants to go to a meeting. He still can't get politics completely out of his system.
Camille still accompanies Cook to many events. She was at his side Thursday, along with three of their children, when Cook was inducted into the East High Hall of Fame as part of the school's 100th anniversary celebration.
She was there two years ago, despite her limitations, when Cook last ran as a candidate that time for county mayor.
During a debate in that campaign, one of the candidates chided Cook publicly for running when he should be caring for his wife. In an emotional response, Cook said he was proud of his wife for being at his side. He likes to take her wherever he goes.
After the meeting, the crowd converged on Cook and Camille with hugs and greetings. "That meant a great deal to me," he told me, with tears in his eyes.
He did regret taking her with him to the South Towne Exposition Center to pitch a petition to get a Utah version of the federal E-verify program on the ballot.
Camille, he recalled, went to a nearby women's restroom. After a while, he noticed she hadn't returned. Cook panicked as he and several friends, as well as the police, scoured the Sandy convention center for his missing wife. She had wandered away, but finally was spotted on the opposite side of the large building.
"I'll never again leave her without an escort," he said.
During our interview, Cook's daughters Michelle and Alison accompanied their parents, who are both 67. They entertained their mother with songs, smiles and laughter. She grinned nearly the entire time. I sensed that she knew she was surrounded by loved ones.
I asked Merrill if he felt this experience has deepened the strong bond he has shared with his wife for more than four decades.
"Yes," said Camille, as her gaze turned to me.
Later, as we were leaving and Cook was saying goodbye at the front door, Camille gave him a hug and told him she loved him. The once-bellicose politician then gently kissed her on the top of her head.