This part of the post jumped out at me from a pit thread on Iowa supremes. With a signifigant portion of a states national guard either in the rockpile or the sandpit, who is available to be called up if Iowa, or any particular state requires them for relief , or what not.
after Katrina, Louisiana asked states all over the country to send National Guard units. Some of the Lousiana Guard were in Iraq at the time. For a short while we had Michigan (I think it was) guard units in our town. What was unusual, at least to me, was that the Democratic Governor of La. avoided working through the Federal Gov’t and apparently contacted the other states directly. Obviously there was a lot of DoD involvement, but at least some of the National Guard interaction was state to state.