By late January 2021, just days into Donald J. Trump’s unhappy new life as a former president, his world had shrunk to a size he could not abide.

Self-exiled in Florida as a twice-impeached semi-pariah, he golfed and glowered, boiling over his 2020 defeat and still refusing to acknowledge its legitimacy. His social media bullhorns had been silenced after Jan. 6, with Twitter citing “the risk of further incitement of violence.” His circle had dwindled to a smattering of junior aides, straining to keep him on the fairways and away from the television.

“Get the pool,” Mr. Trump instructed at one point, referring to the hive of reporters who had trailed him daily as president. “I want to make a statement.” He was told that he did not have one anymore.

By late February, Mr. Trump had waited long enough. In his first public appearance as a newly private citizen, he accepted an invitation to Orlando for a conference of right-wing activists.

“Do you miss me yet?” he asked, his arms splayed wide, as if waiting to be hugged.

It had been five weeks. Outside of that room, most Americans did not seem to miss him much at all.

Now, less than four years later, Mr. Trump’s arc back to power is complete — an extraordinary reversal carried off by a man who never especially changed, never accepted the reality of his 2020 loss, never stopped understanding the core of his own rampaging appeal, never doubted that he could bulldoze anyone in his way.