In Black Lamb and Grey Falcon, Rebecca West mentions that Tsarist Russia had a policy of "marching on" any insurrection against a reigning monarch in Europe. This support being given regardless of Russia's predisposition towards said monarchy (I don't have my copy at hand, I only remember this being in one of the Zagreb chapters). Is this documented elsewhere? Was this policy ever referenced or acted upon, whether by threat or by actual mobilization of forces by the Tsarist regime?
Widening the scope of this question, it seems to me that Russian authors of the 19th century were preoccupied by affect revolutions and new ideas of government in Europe may have on the Tsarist state. Specifically, in say, Fathers and Sons and Crime and Punishment, the authors were troubled by the influence socialists and nihilists abroad may have on the Russian people, and that revolutions in Europe may foment restlessness in Russia. Was this mirroring (Or mirrored?) the concerns of the Tsars, who put in place a policy such as above in order to nip such problems in the bud?
Finally, and this is probably far too large a generalization, when I thought about this, it seemed like a very "modern" notion to me. "Modern" in the sense that the mentioned policy of immediately putting down a revolution before it can "corrupt" neighbouring states (Exclusively via novel ideas of government, as opposed to, say, religious ideas or outright force of arms) wouldn't sound out of place in the discourse of the 20th and 21st century - the immediate example being the domino theory in the Cold War. Are there earlier examples of such thought? That is, a regime before the 19th century that was worried for its stability due to a novel form of government coming to power in a completely different geographic area, not due to the latter being considered a martial or economic threat, but purely (At least, ostensibly and explicitly) due to these new political ideas "infecting" (I don't mean this, personally, in a pejorative sense, but it's the best term that comes to mind) to local populace?
Any insight would be most welcome. I would be especially thankful for directions on further reading on this subject (If this is actually considered a matter cohesive enough to warrant its own terminology and study).
Actually, such a way of thinking was widespread among all European monarchs. Especially after the French revolution, states like UK, Prussia, Austria and Russia worked TOGETHER to crush revolutions and insurrections. Austria was famous for doing so in Italy in the 1820s, 30s, and 40s. Prussia and Austria together crushed insurrections throughout the German states. Austria and Russia politicked a lot in sorting out the Balkans issues in order to prevent wild annexations, or even the rise of independent states (Slavic, thus loyal to Russia and hostile to Austria ruling its own Slavic minorities)) as nationalism spread like wildfire and the Slavic peoples rose up against Ottoman dominion.
Austria in fact organised the Conference of Vienna in 1815 in order to re-institute the Ancien Regime, and states pledged to aid each other against revolution.
One might think that a monarchy might benefit from their rival, e.g. Austria vs Prussia, falling prey to revolutionaries and thus instability and chaos. But the rulers were more astute than one tends to give them credit, and they saw that if a revolution succeeded in one part of Europe, it would encourage revolutionaries in other parts of Europe - such as Austria and its multi-ethnic empire, explaining their big role in crushing revolutions throughout the 1800s, particularly the liberal revolutions of 1848 which started in Paris and spread to Italy, Germany, and even into the courts of Russia.
Also, even though monarchies were rivals, they tended to be blood-related and thus when one ruler was faced with rebellion from the peasants, it was only appropriate to intervene. :)
So yes, while it may seem "modern", it isn't really. Its been a way of thinking by the absolutist rulers ever since the armies of Napoleon marched across the continent. A modern example is the role of Saudi Arabia in the Middle East, trying to crush the Muslim Brotherhood from Tunisia to Egypt to Syria as the Saudis view this group as a revolutionary threat against their own order, and thus have heavy roles in financing the Sisi regime, militias in Libya, Syria and Iraq, all with the hope of preventing revolutionaries and Jihadi groups from influencing or even infiltrating the Saudi absolutist Kingdom. The Saudis also use their Salafi preachers to spread propaganda against groups like the Muslim Brotherhood, in a similar way the Church preached against the devils ideology of liberalism and democracy in Europe.
However pre-19th century, I can't particularly think of examples other than the Italian republics such as Florence, Milan and Venice who regularly fought against both French and German (Holy Roman Empire) dominion, who saw the Italians as little upstarts and ripe for the plucking. This is probably because before the enlightenment period, and even the Renaissance, Europe and indeed most of the world did not know another form other than royal, hereditary rule. The Renaissance brought to popularity the ideas of Republic and Democracy from the Romans and Greeks. This was something rulers initially took advantage off to throw off the yoke of the Catholic Church, institute secular rule to improve their own powers and be able to do as they wish - such as divorce wives, and confiscate church lands.
I really recommend books such as:
Frederick the Great, Timm Blanning
Iron Kingdom, The Rise and Downfall of Prussia, Christopher Clark
Otto Von Bismarck, Jonathan Steinberg
And really, any major publication on Napoleon, which is the primary trigger of these European revolutions, and thus in relation to your question, the interventions. The books I recommend (and are sources in my answer here too) are German-orientated yes, but they do a good job of exploring the politics of the time - the Enlightenment period of the 1700s and how it changed Law, and the 1800s and how Napoleon and the subsequent returned Ancien Regime Order also dealt with the revolutions and spread of liberalism/nationalism throughout the 1800s.