This comment states that the modern left is often promoting federal powers over state powers.
I assume that the comment relates to the United States. It surprises me, because in (northern) Europe, some left-wing and most hard-left parties are quite critical of the European Union, arguing that democracy works better on a smaller scale level, that a strong concentration of power is bad (e.g. increases susceptibility to corporate corruption), that the European Union is mostly a neoliberal project, among other arguments. Examples include Socialistische Partĳ in The Netherlands, Vänsterpartiet in Sweden, Die Linke in Germany, PCF in France, etc. Danish People's Movement against the EU sits with the European United Left group. Jeremy Corbyn in the UK has also historically been quite lukewarm about the EU. This is unlike centrist parties, such as the ones by Tony Blair and Gerhard Schröder, which often strongly endorse any (federalist) plans from the EU.
Do left-wing parties in the USA promote federal powers over state powers? If so, what is the reasoning behind this? Is this just a remnant of state powers being a substitute for southern states wanting to maintain first slavery, then segregation, or is there some more fundamental reason behind this?