https://en.wikipedia.org/wiki/Overthrow_of_the_Hawaiian_King...
The current difference is that now it's happenning during a live broadcast, and the actions are being tried to be justified (as "justice") through existing legal frameworks.
That's one of the ways Empires grow their periphery regions. Another way is when an Empire spreads its culture and abundance to orbiting regions, so that inhabitants of the periphery get a personal interest in becoming the part of the Empire and bringing a change to their governing bodies to align with the metropolis.
Just as a point of comparison (not justifying russia or the US), the region of donetsk (and crimea) was supermajority ethnically russian, and by the time the US overthrew the hawaiian kingdom, ethnic hawaiians were a minority within the (mostly imported) population, so in the case of both russia and the US's actions the majority of local populace gained political power in the aftermath of the takeovers:
https://www.hawaiiankingdom.org/info-census1890.shtml
By comparison if you consider HKers ethnically distinct from mainland chinese (on cultural bases), the situation is dramatically different.
Seems to me that everyone wants to cast their war as a just war [0]. If that means deniable approaches or false flag operations [1] then so be it. In particular I found this excerpt from [1] ironic in the context of your comment:
> Russo-Swedish War
In 1788, the head tailor at the Royal Swedish Opera received an order to sew a number of Russian military uniforms. These were then used by the Swedes to stage an attack on Puumala, a Swedish outpost on the Russo-Swedish border, on 27 June 1788. This caused an outrage in Stockholm and impressed the Riksdag of the Estates, the Swedish national assembly, who until then had refused to agree to an offensive war against Russia. The Puumala incident allowed King Gustav III of Sweden, who lacked the constitutional authority to initiate unprovoked hostilities without the Estates' consent, to launch the Russo-Swedish War (1788–1790).
[0] https://en.wikipedia.org/wiki/Just_war_theory [1] https://en.wikipedia.org/wiki/False_flag
In contrast a good example of psychological warfare would be when Russia organized a protest and an attendant counter-protest in Texas that were made to appear "organic."[0] So the difference between the two is that one proudly has an official "Russia" label on it and the other is clandestine.
[0] https://www.texastribune.org/2017/11/01/russian-facebook-pag...
Ukraine is more hybrid warfare.
HK is more lawfare.
Chinese maritime disputes is more gray zone warfare.
Now none of these claims withstand any sort of legal scrutiny, but that's not the point. In the year or so it takes the Hague to spell out the obvious, that the Russian military in coordination with the Russian presidency created a bogus legal argument that aligns with their strategic goal of annexing as much of Eastern Europe as possible, the invasion is already completed and Donetsk is effectively a Russian vassal in the middle of Ukranian territory.
Just like in the time of the American Revolution guerilla tactics were innovations to the stodgy preconceptions of war that the British had, where they believed a gentleman's war should be fought by squares of men taken broadsides at regular intervals, we must recognize that armed conflicts today are always accompanied by legal warfare, the legal activities that support broader strategic objectives.