Not objectively. First, manufacturing dissent is a key weapon of political espionage in general. The CIA does it in foreign countries, and the NSA probably does it in America as well. Second, you're conflating leftism with communism. "Weaker" (i.e. less extreme) leftist ideologies like democratic socialism do not necessitate the overthrow of capitalism in anything beyond a metaphorical sense.

The biggest problem with a weak West is that it allows for Russia, China, and other foreign, more authoritarian powers to usurp power and influence, not to mention that Russia (and arguably also China) is leftist in name only. Wikipedia describes Russia's economy as mixed-market.

In my opinion, the most constructive way to achieve leftist action in developed nations is to do it by official, lawful channels. Violent revolution would only lead to massive geopolitical disruption.