Wilson Shannon found out that men at the Wakarusa camp intended to intercept his message Colonel Sumner and the 1st Cavalry after he visited Lawrence, but it confirmed the danger he already suspected from both touring the camp and speaking with the proslavery militia’s leaders. He also had other, possibly worse news about the town’s besiegers. George Douglas Brewerton prints a letter from J. C. Anderson, which Shannon’s office neglected in the rush of events to note the date or time. Anderson, who Brewerton introduces as a member of the Kansas Assembly, wrote to militia general William P. Richardson, who passed word on. The legislator had
reason to believe from rumors in camp that before tomorrow morning the black flag will be hoisted, when nine out of ten will rally round it, and march without orders upon Lawrence. The forces at the Lecompton camp fully understand the plot, and will fight under the same banner.
Brewerton’s footnote describes the black flag as a generic signal, but raising the black flag had another meaning in the nineteenth century. A black flag meant no quarter. One raised it not just to declare the hour at hand, but also to promise merciless slaughter. If the people of Lawrence feared their home becoming a second Greytown, then their besiegers hoped and planned for it.
Shannon’s letter of the sixth to Sumner, the one nearly intercepted, suggests that he had Anderson’s missive on hand at the time of writing:
It is hard to restrain the men here (they are beyond my power, or at least soon will be), from making an attack upon Lawrence
The Governor could have written this regardless of Anderson, possibly relying on Samuel Jones’ report of the unruly camp as well as his own impressions, but Shannon must have thought himself in at least limited control of the army to fret after losing that control in the near future. Anderson’s rumors would necessarily entail that loss. He also introduces a further wrinkle into the story:
If Governor Shannon will pledge himself not to allow any United States officer to interfere with the arms belonging to the United States now in their possession, and, in case there is not battle, order the United States forces off at once, and retain the militia, provided any force is retained, all will be well
Brewerton explains in another footnote that some of the Missourians had taken muskets from a federal arsenal in their vicinity before coming to Kansas. If they had done so, which seems likely considering at least some Missourians came over in militia formations, then the besiegers had more to worry about than just missing some mayhem. The 1st Cavalry might decide, reasonably enough, that they had stolen the guns and must surrender them at once. The mere presence of United States forces interposed between the proslavery men and Lawrence would likely prevent bloodshed, but if they came into the camps demanding the arms that might bring on a clash of arms with the military.
That in itself might deter some proslavery men, but they had to know that the 1st Cavalry remained at Fort Leavenworth. If they could sack Lawrence expeditiously, they might finish the job and surrender any arms asked of them without trouble thereafter. Anderson, understandably, closed by urging “speedy measures” and fearing that things might already have gone past the point of no return.