There are plenty of examples of leftists not being protectionist. The Girondins of revolutionary France were very pro free market, something that lost them a lot of support among the starving sans culottes. The more radical Mountain factions appear to have mostly supported protectionist measures, namely maximum prices, largely out of the need to stop the mobs of Paris from literally storming the legislative halls. The moment the parisians believed that the maximum didn’t work, they were dropped.
actual communism and socialism was internationalist at its core.
Internationalist yes, but not pro-free-trade. And in practice it was always almost always the opposite of that.
In Europe all the hard-left parties were anti-EU precisely because they were opposed to free trade and wanted to protect the local markets.
Currently in the United States the liberal party is the party of free trade while the right-wing president calls himself the Tarriff Man.
1. The Democrats are not leftists. Liberals are not leftists.
2. Ideologically speaking both US Republicans and US Democrats are Liberals and pro-free trade, Trump is an exception.
Language changes, and in American English at least, the definition of liberal has changed. If you use the word liberal to describe what we might refer to as "classical liberal", you will needlessly confuse people.
Kind of an outlier, though, because the Republicans typically cheer free trade (but then put tarrifs on shoes, cheese, tires, etc, etc, and of course subsidize big agribusineess, Wall St., etc).
> the Republicans typically cheer free trade
These affinities have shifted many times in American political history. For example, Lincoln was a Republican.