We focus so much on arguing over who is at fault in this country that I think sometimes we fail to alert on what's actually happening. I would just like to point out, without attempting to assign blame, that American political institutions appear to be losing common knowledge of their legitimacy, and abandoning certain important traditions of cooperative governance. It would be slightly hyperbolic, but not unreasonable to me, to term what has happened "democratic backsliding".
Let's imagine America of 2012 was measured 0.8 on the fictionally accurate "legitimate democracy index", and Hungary of 2012 was measured 0.5. My thesis is that we'd now be at 0.75, and that our regressions seem to have calcified despite a calming culture war. Within the last three or four years we have seen:
- The world's largest protest-riot ever, when measured by estimated damage to property.
- The leader of the opposition party being arrested on a mix of real and recently-invented process crimes in several different jurisdictions a year before his campaign.
- A presidential candidate openly contesting an election as fradulent; a third[1] of Americans coming to believe that our last presidential election was probably or definitely illegitimate.
- Spontaneous mob assaults of the capitol building.
- Recent, and novel, legislative movements by Republicans to censure and fine Democratic congressmen millions of dollars outside of the criminal justice system.[2]
- Serious and underreported attempts at dramatically expanding political control over the civil service[3] and, if you'll permit me to speak anecdotally, serious and successful attempts at unprecedented political loyalty testing of appointed silovik.
You can disagree with how any one political faction is characterizing the above events, or how I'm characterizing the above events. But I think that's missing the point. Maybe Donald Trump is a clown and all of his indictments are perfectly legitimate and that they ultimately demonstrate the dispassionate fairness of our nation's prosecutors. Even if that's the case, perception is the leading indicator for democratic stability, and a large amount of Republicans do not agree. Since Republicans now believe that the arrests are politically motivated, and that Democrats are defecting against longstanding political norms, they are pressuring their politicians to escalate[2][4] and calling them traitors when they refuse to do so. Democrats, in turn, will see this behavior and change their posture whether the election was actually stolen to begin with or not.
It's possible to exaggerate the danger. I do not expect the entire political system of the United States to change anytime soon. But since 1989 I think it has been appropriate to have a degree of knightian uncertainty in predicting the eternal dominance of this or that regime, on the basis that modern technology and secret police make resistance impossible. If you currently habitually round probabilities of serious repression or further democratic backsliding in the West to zero, I suggest moving that up to 1%-per-decade and spending a little bit of time thinking about what you'd do if this continues for five more years and your estimate increases to 5 or 10 percent.
That's another highly contentious assertion. Even at the height of Vietnam, the US never considered Southeast Asia to be the main domain of competition against the Soviet Union. The primary focus was always on fielding a military force capable of challenging the Soviets in Western Europe. Indeed, one of the reasons the US failed in Vietnam is because the military was unwilling to commit its best units and commanders to what the generals perceived was a sideshow.
Was the US ever allied with China? What we did as a result of the Sino-Soviet split was simply let the People's Republic of China back into the international system from which they had been excluded. The US certainly did not pursue any greater alignment with China until much later, at which point the Soviet Union was well into its terminal decline.
More evidence is needed. The oil shocks were certainly very visible, but it's not clear from the statistical data that they did much damage to the US economy. In fact, the political response to the oil shocks (rationing, price controls, etc) did arguably more to hurt the economy than the oil shocks themselves.
The actual readiness of Soviet forces, as opposed to the hilariously false readiness reports published by unit commanders, is a matter of great debate. After the Cold War, when US commanders had a chance to tour Soviet facilities in ex-Warsaw Pact states, they were shocked at the poor level of repair of equipment and poor level of readiness among the troops. Furthermore, by the Soviets' own admission, the performance of their troops in Afghanistan wasn't very good, even when compared against the relatively poor level of training and equipment of the insurgent forces.
Vietnam was certainly a blow to US power, but it was nowhere near as serious a blow as you seem to believe.