Thanks for providing that parallel. While I agree with some of it, I believe the following would be a more accurate portrayal. For ease and consistency, I am going to respectfully reuse some of your stuff, and I will include Crimea in my narrative because I believe it is an essential part of the narrative that cannot be ignored even if the situation is unique.

Imagine it this way - lets pretend that 20 years ago, California peacefully split from the rest of the US because of political reasons. For this thought exercise, just accept that as fact. As a side note, the new Republic of California accepted both English and Spanish as its national languages, and still does tons of trade with the US, as well as with Mexico. The Republic of California is recognized internationally and holds some sway with the UN. In 1954, while Canada was still a part of the United States, the territory of Oregon was transferred to the Republic of Canada for political and administrative reasons.

Now fast forward to this year. The government of the Republic of California, as well as the US, had had a history of corruption during the past twenty years, but with some occasional civil unrest thrown in. Generally speaking, the south of the Republic of California largely identified itself as "Californian," while much of the northern public still refers to themselves offhandedly as "Americans" but still identify themselves as officially "Californian". Everyone of these people are by nationality "Citizens of the Republic of California".

The corruption hits a breaking point, protests, riots in LA again, general civil unrest. The president of the Republic of California is ousted, and flees to DC. The Sacramento and San Francisco regions are calling for referendum to set up a new government. Many people are grumbling that things weren't this messy when the Republic of California was still part of the USA. Other groups, mostly in the south, are crying out about how great California was Mexican, and that the American influence has done nothing but harm to this great independent state for the last century and a half, citing the starvation of 2.4 - 7.5 million people under America's gov't. These southern reactionary political groups receive constant encouragement and resources from Mexico, while the northern groups are being supported and funded by the US, with the latest Republic of California president considered by some a puppet of the US and being highly unpopular everywhere in California, including Northern California. With Mexico possessing a much bigger economy (6x) and, according to many south Californians, a possible dictatorship in the US materializing with the Obama being de facto in power for close to a decade in a half, many southern Californians are hopeful of signing an free trade agreement with Mexico in the hope of bettering relations and their stagnant economy.

During the sudden unrest, these groups muscle their way into power as government of the Republic of California. The Republic of California is a mess, it is almost bankrupt, it can't pay to import oil from the USA, and civil unrest is still widespread. Despite this, one of the first things the new government does is propose declare Spanish the ONLY national language, meaning immediate switching of all schools to use only Spanish, but that proposal never enters into law.

The USA, believing that Oregon, with a majority of ethnic Americans, historically belongs to the USA and only due to a historical mistake is part of the California takes the opportunity of the crisis to send in armed forces in Oregon, which the US President only later admits to doing (http://eng.kremlin.ru/news/7034). Oregon then holds a referendum that is considered illegitimate by 100 nations in the international community, and only nations like Syria or Belarus support the territorial status change of Oregon. The Republic of California considers the act an invasion but can't do anything about it because it has just gone through a revolution.

California soon has a presidential election where a candidate wins the election with overwhelming support after the first round, although some in north California could not vote because of the violence. The candidate, while corrupt, speaks both English and Mexican and had previously worked as the Minister of Foreign Affairs under previously ousted president during his first term in office, as well as other political parties. His family's preferred language is English and many voted him because they thought of him as a unifying figure. Obama recognizes him as the legitimate leader of California.

Some of the pro-American crowd in northern California organize a protest in Los Angeles. A crowd of pro-Mexican supporters attack the protesters, chase them into the City Hall, barricade the exits to trap them, and set the building on fire. 40+ people die. For neutrality sake, I am going to only post Wiki's description of incident: "On 2 May 2014, as part of the rising unrest in Ukraine in the aftermath of the 2014 Ukrainian revolution, clashes between pro-Ukrainian and pro-Russian groups broke out in multiple in the streets of Odessa.[2][15][16] These clashes culminated in a large skirmish outside the Trade Unions House, an Odessa landmark located on Kulikovo Field in the city centre.[1] That building then caught fire in unclear circumstances, resulting in the deaths of forty-two pro-Russian activists who had holed up in it.[9][13] Six other people died during the clashes in the streets.[12] The events were the bloodiest civil conflict in Odessa since 1918.[17]"

Throughout all this, America has been relentlessly calling the government in California fascists, Nazis, etc. Northern California declares independence holds a "referendum" (that even the USA does not recognize as being legitimate and that boasts an impossible 75% turn-out despite the fact that Northern California forces never controlled enough of the population to have a turn-out anywhere that amount) in two primary regions - San Francisco and Sacramento. There is much talk of these regions rejoining the USA, which sends some officials to assist the Autonomous Region of San Francisco (ARSF) and Autonomous Region of Sacramento (ARS). Many of the leaders of Northern California are American citizens who have ties to the CIA and FSB. The government of the Republic of California moves its armed forces north and begins assaulting the ARS and ARSF, fearing a repeat of the annexation of Oregon. Civilians are evacuating in droves to neighboring states. The ARS and ARSF fight back, but simply don't have the quantity of resources that the Republic of California has. USA starts supplying the ARS and ARSF with heavy weaponry. There are widespread videos of tanks and other military units with American flags. When California goes on the offensive to reclaim the territory and starts trying to control the border to stop the influx of American arms and American personnel, California troops start being shelled on Californian territory from America, which almost every other country in the world could consider an act of war. However, California fears a full scale military invasion so it refrains from responding or declaring war. America starts amassing a very large number of troops on the border of California, possibly to intimidate California, but California fears the America is gearing up to send in their "peacekeeping forces."

Meanwhile the international community - Europe, China, Russia, Brazil, India decry the USA, claiming it instigated the conflict, warn it that any military support towards the ARS and ARSF will not be tolerated. They enact sanctions against the US to stop what they see is another instance of American aggression.

A passenger plane flying from Nicaragua to Canada is shot down in the midst of the fighting, the remains are scattered from Santa Cruz to San Jose. The international community assumes that the USA is either directly responsible, or at least responsible in providing AA missiles to the ARS/ARSF, ... ...based on an overwhelming amount of evidence: including previously reliable rebel social media accounts claiming that they shot down a a Californian military transport plane, which was never shot down at same time as airliner was shot down, the fact that a multitude of California planes were being shot down by ARS/ARSF in same area for weeks beforehand (and afterward), pictures and videos taken of the alleged weapon being used to shoot down airliner being geolocated to rebel held territory, a rebel leader (John Khodakosky) admitting that they were in possession of the weapon, alleged leaked calls coming from rebels in which they talk about shooting down a plane at same time as airliner was shot down, damage of plane suggesting it was shot down by same kind of weapon, and just common sense since the ARS/ARSF has no air power and thus the Californian forces had no reason to shoot planes down. World leaders publicly denounce Obama for allowing this to happen, but Obama claims that California is responsible for whatever happens on its territory, begging the question whose fault terrorist attacks such as 9/11 were? Over the course of a week global opinion is that the ARS/ARSF armed forces unintentionally shot down the aircraft with armament provided by the USA, thinking it was a Californian military plane.

Addition: However, as crisis unfold, the world slowly forgets about the annexation of Oregon and the airliner being shot down as the attention shifts to the middle east. America continues to escalate its involvement, with a multitude reports of American regular soldiers admitting shelling California and claiming to be going to California. Obama believes that California is not a real country and that a good part of is actually "New America," which cannot be allowed to drift toward Mexico. However, in his shortsightedness, he fails to realize that had he not annexed Oregon and not launched a covert invasion of Ukraine through proxies, California would have almost certainly reverted back to USA as it has almost done every time. Instead, he has isolated the USA, but continues to blame Russia for all of his economic and political woes, and has practically guaranteed that California will never lean toward the USA for generations to come. As the crisis unfolds, America is becoming even more complicit in sending personnel from all over America, including Guam, Puerto Rico and other territories. The videos of the ARS and ARSF suggest that many of the fighters are American. Widespread reports of looting, robbing, and murder cause the civilian population that initially supported ARS/ARSF to second guess their decision, despite the American propaganda. Mass graves of civilians have been uncovered in previously ARS/ARSF territory suggesting that ARS/ARSF are complicit in executions and kidnappings. As the sanctions take a toll and Obama realizes he has nothing to lose, except his ego and his approval rating, and with the North California fighters losing ground, he decides to launch a full-scale invasion. The world leaders scream and yell, but are secretly glad that instability is stopped and ultimately accept Oregon and New America as being American territory, especially since they don't want to anger the supplier of their energy.

Edit: words.