Answer:
The best brief description of Louis Riel is "clever but unbalanced."
Riel's sanity during the so-called Red River Rebellion (the formation of the provisional government in 1868-70) is questionable. His legal analysis of the situation which led to the formation of the provisional government, however, was quite sound.
There is little doubt among historians concerning the period during which he led the North West Rebellion of 1885. Riel was then clearly not sane.