Phil Mickelson follows through on a chip during a practice round at Pinehurst. (Streeter Lecka/Getty Images)

His swing is still remarkable, fluid and natural but powerful all the same, and when Phil Mickelson stood late Tuesday morning on the tee of Pinehurst No. 2’s 15th hole, it could have been 1999 all over again. He pulled a 6-iron he thought could cover the 204 yards, even though caddie Jim “Bones” Mackay preferred a 5, and he laid into it, pin-high. The gallery, which filled all the seats in the grandstand behind the green and lined the ropes four deep, applauded.

Jordan Spieth, one of three 20-somethings in Mickelson’s foursome, looked incredulously at Mickelson. “Six?” he mouthed. No way he hit a 6-iron some 200 yards into the wind. It must have been gamesmanship.

“I crushed it,” Mickelson said.

So here he is again, at the U.S. Open, at Pinehurst, at his swaggering, self-confident best, recent results and off-the-course distractions be damned. When he first came here 15 years ago, he was a father-to-be rather than a father of three. He didn’t yet have a major title, and now he has five. He didn’t yet have the private jet, the $73 million in earnings on the PGA Tour alone. And he sure didn’t have the gaping wounds, some of which still need suturing, from his 23 previous trips to the U.S. Open.

There is no character among the 156 in the field who will be more central when the proceedings begin Thursday morning. Even the remembrances of the late Payne Stewart — who won the 1999 title here with a par-saving putt at the last, then died in a plane crash four months later — involve Mickelson, because it was their riveting duel over the back nine on that rainy Sunday that defined the tournament, and because it was Mickelson’s face Stewart grabbed amidst the bedlam at 18. Stewart told him, right there on the green, that he would win U.S. Opens in the future, but that there’s nothing better than fatherhood.

Mickelson has realized just half that. His daughter Amanda was born the day after the 1999 Open, and Sophia and Evan followed in the ensuing four years. Last June, as he prepared for another U.S. Open at Merion, he took a cross-country flight to San Diego to hear Amanda speak at her eighth-grade graduation, then hopped the red-eye back to make it for his first-round tee time. He led after each of the first three days, only to stumble over the final eight holes on Sunday and lose to Justin Rose.

No one else without a U.S. Open trophy has more than four runner-up finishes. Mickelson has six. It is, then, a complicated relationship with a tournament he could well loathe but says he holds dear. Added this year, because he took the British Open last July: the fact that a victory at the Open would give him titles in all four majors, something accomplished only by the best ever to play, Ben Hogan and Jack Nicklaus and Gary Player and Gene Sarazen and Tiger Woods.

“It’s a career goal of mine to win all four majors,” Mickelson said. “I feel like the five players that have done that have separated themselves from the other players throughout all time. It shows that they have a complete game. If I’m able to do that, I feel I would look upon my own career differently.”

He is in that odd spot, in the midst of his career while simultaneously being able to reflect upon it. He turns 44 Monday, but instantly offered Tuesday afternoon: “I don’t feel old.” And the way he hits it, still pure and straight and long when he needs it, that makes sense.

“He’s a Hall of Famer,” said Justin Thomas, a 21-year-old Tour player who joined Mickelson in Tuesday’s practice round. It is how the next generation thinks of Mickelson, even as he helps make them feel like peers. Tuesday, he and Rickie Fowler, 25, faced Thomas and Spieth, 20, in the kind of 18-hole match that has become a staple of Mickelson’s weeks at majors.

“I think we’re the only ones who will take him on,” Spieth said, jokingly. But as much as they force each other to putt out, there is an inclusive dynamic here, completely created by Mickelson.

“He’s approachable,” Spieth said. “I’ve played quite a few rounds with him now, and I can talk to him about shots and stuff, but I’ll ask him about non-golf stuff, too. And every now and then, he’ll ask me a question about something.”

On Mickelson’s part, there is intent, too. “What it does for me is it allows me to see what’s coming up,” he said, “and it pushes me to work harder.”

He knows he has work to do. He hasn’t won since the British Open last year, and has no top-10 finishes on the PGA Tour this season. He is fiddling with his putting stroke, committing to a modified “claw” grip for this tournament that he feels will be better on six- to eight-footers.

There are, too, the off-the-course matters. Last week, FBI agents corralled Mickelson at the Memorial Tournament outside Columbus, furthering their investigation into an insider trading scheme that involves billionaire investor Carl Icahn and professional gambler Billy Walters. Mickelson immediately and emphatically professed his innocence, and said he has been cooperating with investigators.

So add that to the differences from 1999, too. He now has some experience in this regard, because in 2009 he played the Open not long after his wife, Amy, had breast cancer diagnosed, and contended at Bethpage.

“When your mind starts to wander . . . you’ve got to get control of your thoughts,” Mickelson said. “Whether it’s outside activities or what’s going on, on the course, you got to be able to control your thoughts and be able to visualize what you want to have happen on just the shot at hand.”

This does not come naturally to him. Here, he not only has the career grand slam and the fringes of the federal investigation to serve as distractions, but there is almost nowhere else to turn for a viable story line. Woods is out following back surgery. Rory McIlroy, Masters champ Bubba Watson and Spieth could all spike interest if they play well into the weekend. But for now, it’s Phil.

“When the focus has ever really, truly been on Phil, he’s always struggled,” said former Ryder Cup captain Paul Azinger, now an analyst for ESPN. “When he’s trying to win the U.S. Open or when he’s trying to become number one in the world or whatever it is, it’s always been difficult for him.”

He does not deny that. But he also understands why he is the story. No one else could make 2014 feel like 1999 again. No one else can right all the past wrongs. No one else has the relationship with Pinehurst and this tournament. It’s Phil, and only Phil.

“I don’t want to put the pressure on that this is the only week that I’ll have a chance,” he said. “I think that I’ll have a number of great opportunities in the future years, but this is certainly as good a chance as I’ll have.”