At issue is the smell of gunsmoke in Dealey Plaza immediately after the assassination. Faced with strong corroboration by several reputable witnesses, Posner accepts the reality of the smell and its identification as gunsmoke, but tries to account for its presence by claiming that the wind was from the north. It wasn't from the north, it was from the west or southwest at the time. The true direction of the wind presents the Lone Assassin theory with some severe difficulties, because the smell cannot be accounted for in the way Posner pretends.

On p. 245 of Case Closed (Anchor Books edition, 1994), Posner mentions that Mrs. Cabell smelled gunpowder immediately after the shots, and in a footnote goes on to mention that Tom Dillard and Senator Yarborough also smelled gunsmoke (both men in fact also said they were gun users and were familiar with the smell). It is well known that others smelled gunsmoke at about the same time (a few seconds after the last shot) in the same area, roughly along Elm Street between the grassy knoll and the TSBD. Discussions of this phenomenon are found in several critical books on the assassination and its investigation. Good summaries can be found in Summers' Conspiracy and in Meagher's Accessories after the Fact, for example. The Warren Commission did not even attempt to account for the smell of smoke and ignored the issue entirely.

Posner tries to convince the reader that the wind direction was from the north. Although he does not give any indication of whether this would help smoke from the sixth floor reach the ground, the implication seems to be that it would: "Although a stiff north-south wind did blow the odor of gunpowder further into the plaza, Yarborough was in the Vice-President's car, two behind the President, and was right in front of the Depository as the shooting began" (p. 245). What Posner has to explain is how Yarborough, who was well to the southwest of the TSBD by the last shot, could possibly have smelled smoke allegedly coming from the sixth floor window. Posner's contention collapses under the weight of physical evidence about the wind direction, which can be shown conclusively to have been from the west or southwest during the assassination.

So, what is Posner's source for the northerly wind? Most of the available evidence (and all physical evidence independent of eyewitness accounts) demonstrates that the wind blew from the west and/or southwest during the shooting. It is impossible for a westerly wind to blow smoke from the sixth floor easternmost window straight down to the street, and Yarborough's car was already a good way along Elm Street, well to the southwest of the Depository itself, by the time of the last shot.

Posner's references for wind speed and direction finally appear a few pages later (p. 255): "Moreover, on the day of the assassination there was a stiff wind blowing north to south, gusting up to twenty miles an hour (162)." Footnote 162 cites Mrs Robert Reid 3H 273, Luke Mooney, 3H 282, Tom Dillard, 6H 165, James Romack, 6H 280, and (without naming him) James Altgens, 7H 517. Here, Posner deviates from the use of physical evidence and relies entirely on selected eyewitnesses' recall.

One might expect that selected evidence cited in an author's footnote would give his thesis solid support. Yet in their cited testimony, Mrs. Reid and Luke Mooney comment only on the wind speed, not its direction. Tom Dillard indeed says the wind blew from the north, and Altgens mentions that ". . .just as I got ready to snap it [the first picture] the north wind caught her [Mrs. Kennedy's] hat and almost blew it off, so she raised her left hand to grab her hat. . . ." But Posner's fifth witness, James Romack, was standing about 100 to 125 yards north of the TSBD, looking south towards the motorcade, and said "[The wind] was blowing into my face. . . The wind was blowing a little bit from the south that day, I can remember." From the south.

Although all these witnesses agree that it was a very breezy day, only two out of five witnesses cited by Posner back his claim that the wind was from the north, and one flatly contradicts him. Posner omitted to cite other very explicit testimony by Officer Martin, one of the motorcycle escort riders, that the wind was not from the north:

Mr. Ball: Was there any breeze that day?

Mr. Martin: Yes; there was.

Mr. Ball: From what direction?

Mr. Martin: I believe it was blowing out of the southwest at that particular location. It seemed like we were going to turn into the wind as we turned off of Houston onto Elm.

Mr. Ball: The wind was in your face?

Mr. Martin: Yes; the best I can recall. (6H 291)

According to weather records from Love Field, at 11:55 the wind was 13 knots, from WSW (approximate bearing 248 degrees). At 12:30 it was again 13 knots, this time from due W (270 degrees). At 1:00pm, the wind had increased to 17 knots and had swung round to WNW (292 degrees) (8 HSCA 21, 173-174). Love Field is about 6 miles from Dealey Plaza, in the direction the prevailing weather was coming from, so these records clearly indicate that the prevailing wind in Dealey Plaza at 12:30 would have been from the W or WSW. The wind was rather gusty and undoubtedly the direction and speed varied somewhat, but not by a consistent 90-100 degrees! Other confirmation for the direction of the wind comes from examining the flags on the limousine. The smaller blue flag trails very nearly straight back along the car, which was heading almost directly into the southwest during the shooting sequence recorded in the Zapruder film. The larger and heavier US flag trails back and hangs over the north side of the limousine, which would be impossible if the wind was blowing strongly from the north through the open Plaza. Elm Street runs directly SW in that area. The flags and their directions can also be seen in the Altgens photo. Although the car was moving, during the latter part of the sequence it is known to have slowed down to about 8 mph, so most of the flag streaming would have been due to the westerly-southwesterly wind and not to motion of the car.

From knowledge of the distance from the corner of the stockade fence, where a puff of smoke was claimed to have been seen by some witnesses, to the areas along Elm Street where smoke was smelled, it is possible to calculate that a 13 knot (15 mph) breeze would take between 5 and 11 seconds to make the journey, depending on the location of each witness who smelled gunsmoke, as cited by Posner and others.

It isn't hard to guess why Posner deceives himself and the reader on this point. It is physically impossible for a stiff westerly wind to blow smoke from the sixth floor window to the street below, but for a northerly wind this might be possible. The best evidence does not support his version of the wind direction. The wind was from the southwest or west.