The author lost me right there. The Republican party we know today was founded in 1854, and could not have "controlled" Congress in 1789.
The Republican party of the early Federal period is the ancestor of the Democrat party.
In 1789, political parties hadn't even developed yet.
If we're going to make a historical case, we need someone who won't make us sound like idiots.
“In 1789, the Republican controlled Congress passed the Northwest Ordinance that prohibited slavery in a federal territory.”
OMG. Epic fail. Perhaps he confuses the Jeffersonian Republicans (ancestors of the democrats) that we refer to today as the “Democratic-Republicans” (much like the Byzantine Empire no one called them that back then) with the modern Republican party which was named to evoke their memory.
That would be triply wrong because that party wasn’t officially formed yet in 1789 and Jeffersonians didn’t have a majority until after the 1800 election anyway! And if they did I doubt they would have agreed to ban slavery in the territory.
Or maybe the author considers the proto-Federalists who controlled the first Congress as Republicans. Weird but that would at least make a tiny bit of sense.
Otherwise seems like a useful article.