1. This 1878 law is a big deal, passed not to keep troops out of the South, but to keep troops from being used against strikes after President Hayes called them out at the bequest of railroad baron Thomas A. Scott during the 1877 Great Railroad Strike.
The 2006 law put into a president's hands the power to use the army against anyone whenever s/he wanted. (It fell under most people's radar screens, and this was a HUGE reworking of our governmental balance of power.)