Effective 2014-08-18, Governor Nixon has called in the Missouri National Guard to handle the escalating civil unrest in Ferguson surrounding the police shooting of Michael Brown. The governor cited "conditions of distress and hazard to safety, welfare, and property" beyond the capabilities of local jurisdictions.
Further, the governor has authorized the superintendent of the Highway Patrol (Colonel Ronald K. Replogle) the authority to restrict and close streets and thoroughfares in the city of Ferguson. This is an escalation of the Curfew declared two days earlier.
Reportedly cops said "about 200" National Guard troops are being brought in.
Text of the Governor's executive order: https://governor.mo.gov/sites/default/files/Executive%20Order%2014-09.pdf
The local CBS News affiliate is reporting Governor Nixon did not consult with the White House before activating the National Guard.
Monday 8/18 around 1:30pm CDT, Gov. Nixon issued a press release saying that the guard's "limited mission" would be to "...provide protection and ensure the safety of our Unified Command Center...."
On Thursday 2014-08-21, Gov. Nixon ordered the National Guard to withdraw from Ferguson.
Background
History of the Missouri National Guard.
Detailed reports of Missouri National Guard's activities in recent US wars: MONG_GWOT_Book.pdf
2014-08-20: National Guard Taps MPs for Ferguson Mobilizations, Military.com
2014-08-18: "Missouri National Guard Has Its Own History of Racial Tension" Mashable