Since getting thrown out of the C.E.O. job at Motorola five years ago, Chris Galvin has lingered in purgatory. He wants out.

So we’re in the offices of Harrison Street Capital, a private equity firm that he founded with his father and brother. It’s on the 35th floor of a downtown Chicago tower, the shore of Lake Michigan far below and Soldier Field in the distance. Galvin’s hair is silver, his eyes blue. I had interviewed him a few times nearly a decade ago at Motorola, but now he comes across as warmer and more forthright than I remember him. Patrician and tidy, he wears a suit, jacket off, while revving up PowerPoint slides on a ThinkPad parked on the blond wood of a conference table.

The slides are the keys to his redemption. There are 121 of them.

Galvin wants to show the world that Motorola’s board made a terrible mistake in getting rid of his family. In 1997, Chris, then 46, became the third Galvin to run Motorola. By that time, the family owned only about 3 percent of the stock, but the company was still the Galvins’ empire. Paul Galvin, Chris’ grandfather, started the firm in 1928. His father, Bob, ran it from 1958 to 1990, building it into an American icon. Motorola made the first commercially successful car radios and military radios, invented the cell phone, and developed the Six Sigma quality-control process. Everyone assumed that Chris would run the place for 20 years. Instead, Motorola crashed, soared, then crashed again. In the fall of 2003, the board shoved him out, replacing him with Ed Zander, a high-energy import from Silicon Valley.

From almost the moment Galvin relinquished the C.E.O. title, Motorola began racking up fantastic successes. In two years, the company posted record results, made the Razr the most popular cell phone ever, and doubled its stock price. Zander got the credit. The events magnified the public’s sense that Galvin had, in fact, been a pleasant but ineffectual heir.

Evicted and demeaned, his company thriving without him, Galvin couldn’t even discuss Motorola without sounding like a whiner. That was his purgatory. “My father’s and my primary passion in life was Motorola,” he tells me, his heritage weighing on him like a kingdom. “Being excommunicated from Motorola was so painful, it is beyond words.”

In 2007, still under Zander, Motorola saw its fortunes plunge again. Activist investor Carl Icahn bought a stake and demanded a change in management. In November, the board fired Zander less than four years after he’d started. (Officially, Zander retired.)

Under new C.E.O. Greg Brown, the company is trying to level off from its dive. In the second quarter of 2008, Motorola eked out a tiny profit on $8 billion in revenue, down $600 million from the same period the year before. The stock got a bit of a boost in August when Motorola hired Sanjay Jha from Qualcomm to be co-C.E.O., but it’s still languishing at its early-1990s level. Following Icahn’s wishes, Brown wants to break the company in two by selling off the cell-phone division. The trouble is, that division is in such bad shape, no one seems interested in buying it. Motorola has lost so much market share and momentum in hot segments like smartphones that the company is in danger of losing its third-place spot in global market share to South Korea’s LG Electronics. (Nokia is the leader; Samsung ranks second.) The Motorola brand looks as if it’s headed for the same boneyard where such once-great American names as Zenith, Westinghouse, and Polaroid are interred.

The mess gave Galvin the opening he’d been waiting for. He commissioned Peter Schwartz, a partner at Monitor Group, a consulting firm, to study Motorola’s publicly available financial numbers. The results, assembled in ­PowerPoint, make the case that Galvin—not Zander—laid the groundwork for the 2004 turnaround. Galvin says he wants Motorola’s story to be a warning about what can happen to long-­established companies when boards and investors focus on quarterly earnings at the expense of long-term strategy. And he’s got a point.

Yet it also seems clear that this is personal. Galvin wants his reputation back. Besides, he needs potential investors in Harrison Street Capital to think of him as a success, not a failure. They’ll invest more money that way.

So Galvin fires up the slide show for me. Amid all the charts and graphs and points and counterpoints lies a simple question: If Motorola dies, who will take the rap?

Or in the lexicon of Dallas: Who shot Motorola?