"The Deaths of Ben Baxter" by Robert Sheckley
Read this story 20-30 years ago but it was probably old then.
1957
A team of operatives (from the future?) tries to influence the actions of one key man to prevent devastation of earth.
A World Planning Council can see results of alternate timelines. It has the capacity to “Switch” Earth to a different timeline, but some differences in our history would produce far worse, or extremely alien, timelines that do more harm than help.
A businessman, Ben Baxter, is so important to preventing total deforestation of Earth that the Council must Switch the world to an alternate timeline in which he does NOT die in an accident after a business meeting with Ned Brynne.
However the Council can not, will not, switch to any alternate timelines that create an outcome equally as devastating, or more so.
The council finds only three acceptable possible timelines. But "currently" Baxter dies as a result of the business appointment in all three of them.
There is enough danger in Switching to an alternate timeline that the council decides to alter a timeline the old-fashioned way – personally go into it and interfere with the meeting by physically stopping Brynne from getting to his appointment with Baxter. That business meeting is apparently the event that causes Baxter’s death in every timeline.
The Council splits into three teams, and each team goes into one of the three timelines. In each of them Ned Brynne has a different personality.
The last is basically 20th century US
All three alternate timelines, Brynnes, Baxters, and meetings are set in New York in 1957. (The time the story was published.)
All Ned Brynnes have an important position beyond their young years. All are veterans of that timeline’s version of the Second World War. In each of them he is intent on a scheduled appointment: a meeting with Baxter at Baxter’s office. In each timeline he goes to a restaurant before the meeting. There the Council teams try conniving, manipulative, or violent methods of stopping Brynne from getting to the meeting.
In two of the three timelines, the conniving fails to stop Brynne from going to Baxter’s office and having the meeting. Ben Baxter dies by various causes during the meeting, in spite of the Council’s efforts to prevent it.
In one world this man is a high-handed snob.
One of his personalities is a highly competent but amoral, hostile businessman who insults a waiter in the restaurant, apparently for offering him French fries, stops the Council members from beating him up in a fight, goes to the meeting, and kills Ben Baxter in another fight.
And he and another man bump into each other accidentally and a duel ensues.
The only “duels” I remember are the first timeline where the hostile Brynne has to fight off the Council members who tried to stop him by force, and Brynne killing Baxter in a fit of rage.
I remember he’s ordering breakfast and the waiter asks him if he wants fries; our protagonist frowns and says, “It is Wednesday” ...
apparently that’s a holy day In this timeline and fries are forbidden
then.
The second timeline Brynne is a Buddhist monk. This one is offered fries by the waiter, and says it is not allowed (within his own faith) that day. He inadvertently embarrasses the waiter. Baxter dies of a sudden plague. (From exposure by a show-and-tell of Brynne's cane.)
The third timeline team meets Brynne in the restaurant, and just tries telling him the truth, reasoning with him to avoid the appointment for the sake of the future of all Earth.
Brynne is half convinced, and goes to Baxter’s office anyway. He has some indecision and leaves just before the meeting.
But this leads Baxter to despair over his troubled business, and Baxter commits suicide.
