Your use of the term "Manchurian Candidate" is inaccurate.
This term more commonly applies to POW's of WWII who were incarcerated in Manchuria, China and supposedly brainwashed.
Depending on the definition of its extent, Manchuria either falls entirely within
China, or is divided between
China and
Russia.
Mind controlled assassin would be more appropriate.
I fail to see how the tragic event at Fort Hood, in your opinion, was orchestrated to discredit the democrats and the Obama presidency.
Inasmuch as Hasan was a Muslim, I would suggest that, if this tragic event was planned, the goal would be to further instill fear of Muslims and the religion of Islam.