Lionel Beehner asks the wrong question:
Rather, we should be asking: Is the world back in a 19th century multipolar paradigm, whereby civil wars were primarily fought between pro-democracy versus conservative/monarchist forces, and the latter typically won because their interventions were more robust and one-sided? As Hironaka and some historians (Sperber 2000) find, during 19th century interventions, the side most willing to use greater force was the anti-democratic side (in this case, typically the Concert of Europe).
In the current context, the anti-democratic axis as it were – that is, the Russia’s and Iran’s of this world [sic] – appear more willing to go “all in” to support their “proxies” than their pro-democracy counterparts in the West.
I’m not sure how useful it is to ask this question, since the answer is pretty clearly no. This doesn’t explain civil wars elsewhere in the world, and it doesn’t describe the Syrian civil war very well, either. The conflict in Syria mostly pits one set of authoritarian regional states that happen to be aligned with the U.S. against another set of authoritarian governments. Authoritarian Gulf states and private donors from these countries have had a huge role in funding and supporting anti-regime forces in Syria. It is more than a little strange to compare the side in the conflict supported by conservative Sunni monarchs to that of 19th-century liberal revolutionaries.
Many Westerners would like to see the Syrian civil war in these terms, or as a replaying of the Spanish Civil War for another generation, but this is mostly just projecting Westerners’ preferences onto anti-regime Syrians. It is a mistake to think of contemporary civil wars in terms of some sort of international contest between democracy and authoritarianism, not least because it creates the false impression that the U.S. and its democratic allies have something at stake in these conflicts when we don’t. There are illiberal authoritarians aplenty on both sides in Syria, but there are hardly any democrats of any kind to be found, and that wouldn’t have been changed by a larger commitment of U.S. resources at any point. The ability to provide arms and funding to anti-regime forces has never been in doubt, but skeptics have been absolutely right to doubt the wisdom and desirability providing this aid.
Regarding Beehner’s larger argument, I don’t think the examples from the 19th century prove the point that he wants to make. Yes, there are several examples of outside intervention in the 19th century that show that foreign powers can end civil wars and revolutions through massive use of force, but that was a world in which the great powers cooperated with one another in suppressing opposition to monarchical rule. There was no chance that any of the other great powers would aid the insurgents, because they were all committed to suppressing revolutionaries wherever they appeared. To the extent that the world today is becoming multipolar, the major powers today don’t agree on how to react to popular and armed uprisings. Some actively support the regime faced with rebellion, others don’t commit to either side, and still others support at least some of the rebels to some degree.
The one-sided 19th-century interventions also involved invading the countries in question and siding with the established governments in brutally suppressing rebels, which is a much more aggressive policy than any that has been seriously discussed for Syria. That makes the conflict in Syria more like the post-1945 civil wars than the civil wars and revolutions of the 19th century as far as outside support is concerned, and it suggests that a much larger commitment to arm and support Syrian rebels from the U.S. and its allies would have fueled an even more destructive and prolonged conflict than the one we are seeing now. At the very least, it is extremely doubtful that this would have made the conflict any shorter or less devastating.