But this achievement is less even impressive than a "OK, we've done the US, now let's look at other countries"

The problem is that the US can export it's carbon-intensive industries and even consume new carbon intensive entities produced by other countries. For example, US investors certainly consume a modest fraction of bitcoins mined in China and bitcoins wind-up consuming not just a lot of energy but also form a new source sort of carbon-intensive production.

Solar and wind power are becoming competitive with oil in general but this can never by itself halt hydrocarbon-energy production 'cause as it's relative price drops, there's always a practical use for hydrocarbon-energy close to the source, where pumping it out of the ground is nearly free.

The United States fully intends to reverse course on that and fire up coal plants in order to something something jobs.

The reason it was falling was because of strict emissions standards and a strong EPA, both of which are basically gone.

If only there weren't other countries that we import goods from. If I drive a car made in Canada, Mexico, China, and the US what do I contribute as a consumer to CO2 production?

It's not even nearly enough. According to the recent UN report, we need cut global net emissions by 50% in the next 12 years, and get to zero net CO2 by 2050. This is a slow-motion catastrophe and people aren't nearly worried enough to take the steps necessary to avert it.

http://nymag.com/intelligencer/2018/10/un-says-climate-genoc...

https://www.vox.com/2016/10/4/13118594/2-degrees-no-more-fos...

Just because you've taken the foot off the accelerator, doesn't mean that we're going to stop before we drive off a cliff.

I've yet to see a plan for a transition to a carbon-neutral economy, even on a 30-year timeline.

Not exactly. The sharpest drop happened "thanks to" the financial crisis, and after that, it has been bouncing up and down depending on the year. The overall trend is downwards though. But not enough, by far.

But the decline hasn’t been monotonic. There have been several years of the past ten where absolute and per-capita CO2 emissions in the US have increased year-over-year.