You are correct and took a few years to be implemented. Plus it was grandfathered in to younger kids. My 18 year old who be voting for the first time tomorrow... did not get hit by common core. My junior in high school did get picked off by common core.
The dems and their media arms are reduced to carping about Trump's occasional misstatements, as if anyone gave a crap. Like you pointed out, they can't argue about the data, so they whinge about Trump's blustering. For MAGA, it's a double treat. We get to enjoy Trump's performance, plus we get to watch the media heads explode. Talk about win-win.