The ironic thing about what Lyon had done was this - his decision to capture Camp Jackson had both worked and backfired. The threat to the St. Louis arsenal had been greatly reduced. At exactly the same time, the threat to the rest of Missouri had jumped to nearly off the scale.
Around the state, news of the 'massacre' in St. Louis prompted a strong reaction. For many tepid Missouri Unionists, the Camp Jackson Affair turned them firmly away from the Union and, almost by default, toward the Confederacy. (For some perhaps, the fact that Frost and his men at Camp Jackson had wanted to do to Lyon exactly what Lyon had done to them was apparently beside the point.) Others remained just as firmly pro-Union.
But in the wake of Camp Jackson, the middle ground between pro-Union and pro-Confederate was rapidly growing too small to stand on. A reluctant population was being forced into choosing sides.
In St. Louis itself, hundreds of people fled the city in fear for their lives. More violence had broken out on the night of May 10th, though probably not as much as might have been expected. Nonetheless, more people had been killed. The following day, another encounter between civilians and a detachment of Lyon's soldiers resulted in yet more deaths.
On the political front, news of Camp Jackson prompted the state legislature to quickly pass a controversial military bill, granting increased power to Governor Jackson in order to place the state on a firmer war footing. Recruits were soon flocking to join the Missouri State Guard.
On May 11th, one day following the Camp Jackson Affair, William S. Harney returned to the scene, replacing Lyon as commander of the Department of the West. Given their past history and the present situation, it seemed reasonable to expect that Lyon was not long for his present job.
Much to everyone's surprise, Harney not only took no action against Lyon, he actually endorsed what his brash subordinate had done. At least officially.
Privately, Harney still harbored serious reservations about Lyon; but the long-time army veteran had also begun to suspect, with good reason, that Jackson and his supporters had not been dealing from the top of the deck. (For that matter neither had Lyon or Blair. It was the nature of the game in 1861 Missouri.)
In addition, as historian Christopher Phillips points out, Harney was probably in no great hurry to again cross swords with Lyon's benefactor, Frank Blair, Jr. To oppose Lyon was to oppose Blair, and as Harney had already discovered, to oppose the powerful Frank Blair was a very risky career move.
