With a 10-under-par total, Kaymer has a 6-shot lead heading into the third round, tying the largest 36-hole lead in the championship's 114-year history.
How do players mount a charge against Kaymer, who has been seemingly invincible to golf's stiffest annual challenge?
Do they attack the course more aggressively to try to put up some low numbers and pressure the leader? Do they abandon the very careful and conservative approach that many of them brought into this week of laying back off the tee with irons and hybrids and playing safe approaches to the greens?
Or do they wait for the 29-year-old German to stumble and come back to the field?
Perhaps, the chasers could get aid from Mother Nature.
"Maybe it [the course] getting softer is the best chance," said Adam Scott, who is even par for the championship after shooting a 3-under 67 on Friday. "Because if guys start making birdies, maybe he'll feel a little more pressure to make some, and you just don't make them because you want to out at a U.S. Open, even if it's soft.
"You've got to hit great shots, and maybe if it softens up, it's a better chance for people to catch him."
Scott's perfect plan over the next 27 holes would be to cut Kaymer's lead to less than half. And then, he said, anything can happen over the final nine holes at the U.S. Open.
This pursuers in this group are either fighting for second place or positioning themselves with some good rounds on Saturday to challenge Kaymer in the final round on Sunday.
Na, who had a 1-under 69 on Friday, said that he isn't changing his strategy.
"I just got to take what I get and play my game, and, hopefully, I can close the gap and a play some pressure," Na said. "If Martin goes out and shoots under par for 36 holes, again, just under par, and stays in double figures, hats off to him. He deserves it."
That's not exactly surrender, but it's not the greatest declaration of war. Perhaps sticking to one's game is the only practical tactic if that's what got you to this point.
Todd, who had a 67 on Friday, also plans to stick to his script.
"I don't think I'll change anything," said Todd, who won the HP Byron Nelson Championship in May. "I hope I get a little bit better every day. If I can go out there and hit a couple more quality shots tomorrow, make one extra putt, [I can] shoot maybe 3- or 4-under again, if the conditions are similar.
"What Martin does really doesn't affect what I do until maybe the back nine on Sunday."
Todd is correct in that you can't play defense in golf. Particularly in stroke play, you're trying to beat the course, and beating competitors is a result of efficiently handling the course. But, as Todd notes, on the back nine on Sunday it can become more like a match-play situation.
"I think you continue to play against the golf course and do the best you can," said Matt Kuchar, who is 1-under par after a 70 on Friday. "I think it's never helpful [to target another player], unless you're within [the] 69th, 71st hole of the tournament, then maybe."
After a 69 on Friday, Henrik Stenson is less rigid on sticking to his outline. "I think I'll stick to my game plan for another nine or 18, at least, and the goal would always be to be within three or five shots with 18 to go. You know you got a chance then if you do something brilliant," said the Swede, who is in the logjam at 2-under.
"Martin's going to need to come back to the field somewhat to give everyone else a chance," McIlroy said after a 2-under 68 to get into the group at 1-under. "But the mindset was [to] go out there and just try and shoot the best score you possibly can and not really care about what's happening on the leaderboard."
In Tiger Woods' prime, his pursuers knew they had to make birdies to catch him. There was no waiting around for the pressure to catch up to him. Kaymer is no Woods, but so far this week on Pinehurst No.2, he's putting on a dominant performance, worthy of the kind of accolades generally bestowed only on the greatest of all time.
This championship could come down to the final nine holes, as many players and fans would like to see, but no one should count on Kaymer coming easily back to the field, because, like his pursuers, he's sticking to his game plan, which makes him dangerous and likely unbeatable this week at Pinehurst.