User blog:2303/Need help with IDNMA

For those, who know US history of the firs half of XIX century.

Major POD for Western Hemisphere in this TL is 1839, when russian adventurer Dmitry Zavalishin try to conqer California from Mexico. Will USA apply the Monroe Doctrine and declares war to Russia or no?

On the one hand, Russia in this time was one of the few US friends, and Martin Van Buren - cautious politican. In the other hand - to permot the violate the Monroe Doctrine means for the USA to drop its prestige.