I recently watched excerpts from "The Squirrel and the Hedgehog", a North Korean cartoon (an idea so twisted, I know), that has both terrible morals, and surprisingly good production values. It is notorious for pushing North Korea's jingoist philisophy onto young children.
Would cartoons in the Comintern be likely to push similar themes.
The UASR seems more militaristic than the OTL USA, and have adopted the idea of spreading Communist ideology (albeit without paving a road to hell, and matching good intentions with good results).
It is indicated that the UASR government is somewhat heavy-handed in enforcing its message in media early on. Eventually, it stops being heavy handed, as people who grew up in the society eventually believe in the message on their own and insert it into their stories.
One the values of the UASR is people running their own militias. But would they use the power of cartoons to push kids into this system. Would Bugs Bunny shoot capitalists? Would Militia Mike be the most popular cartoon character of the post-war generation? What is the psychological effect of all this?
Similarly, would the capitalist states, desperately trying to fight the winds of history, also create political cartoons to influence children?
I've argued before that basically in the UASR, the freedom and number of artists are both increased versus OTL. Indeed in the early years of the 1930s the Party (not so much the state as such) would tend to request that certain kinds of content hammering away at the Party line of the week be the priority, and there would also be some censorship of pre-revolutionary artists trying to smuggle anti-revolutionary themes under the radar--which would definitely happen sometimes, and sometimes they'd get away with it too for a while. But more often the criticism would be picking up on unconscious biases, generally accurately. Surely there will be rather monstrous incidents in which a pretty interesting project would be stillborn, or consigned to obscurity after completion or even destroyed, because of a heavy-handed, half-baked Party member criticism by some big shot. But this would not be the norm as in the USSR because of the wide and deep grassroots of the Party; generally speaking censors would be backed up by a broad consensus of diverse Party members who can judge whether the critic is hitting the nail on the head or not, and if not who will speak up for the right of the artists to distribute their cultural product if they perceive any merit in it at all. So I think even in the 1930s the overall freedom of an artist to put out their vision will be freer than the OTL USA where this ability is first of all governed by economics, and secondarily--if you don't realize that content was subject to quite serious censorship rules in the USA, pretty much from the inception of cinematic art to the present day, and that the state or state agencies would commission works or have strong influence on ostensibly commercial projects (think of say
The Green Berets or
Top Gun--I assume the movie
Navy SEALs is another in this genre though honestly I know nothing about it beyond the title)--if you are not aware that this is reality in the OTL "Free World," that would be an amazing lack of self-insight! I trust that you do realize this and that the anvilicious extremes you can see in the North Korean stuff is a matter of degree, not of a totally different category than OTL. OTL in a layer of influence above the usual leverage the establishment has on generically commercial projects, the US government via the military hired Disney to make the "Why We Fight" series under Frank Capra; but below that layer check out a common commercial project from the WWII years to see all sorts of heavy handed patriotism incorporated quite voluntarily, into Daffy Duck, Donald Duck, and yes Bugs Bunny cartoons, and Three Stooges shorts, and of course big budget studio blockbuster films too.
In the UASR there is positive support for arts in general that does not exist so much OTL; something analogous to the commercial mass markets of OTL exists clearly, and lots of effort will be aimed at successfully being approved and positively reviewed to get into that mainstream--surely it means better funding for the successful collective producing it, and for greater prestige in the art world--in the mainstream of the art world, the idea that what is popular is probably also tending to be what is best artistically will be a lot more prevalent than in OTL, where "stick it to the bourgeois!" was a major rationalization for generations of an iconoclastic stance. A certain, still fairly large, number of artistic people are going to be countersuggestible and tend to push the envelope in various ways, which will lead to some of them being reactionary out of artistic instinct, and I believe the public, overlapping the Party membership quite a lot, will give points for stuff that bucks the mainstream. But generally appreciating that the Revolution has brought a lot more good than harm and that reactionaries are a real threat to the majority, they will also deduct points for reactionary message, and back up formal Party and state critics and censors. What will be real wins for the artists will be pushing the envelope other ways. In addition to the major stream of self-financed work that has major box office appeal, the less successful artists will still have access to sufficient resources, more than in OTL, to produce competing content. The palette of choices for viewing will be wider for UASR citizens, and thus art as a whole, cartoons in particular as a popular example, will be more competitive.
And so even OTL Western works that were clearly influenced by the heavy hand of some strongly prevailing contemporary pro-government ideology often have artistic integrity and are, as propaganda, much stronger in their effect than stuff that has been typecast by some ideological hack--in the UASR, the boundary between "Party propaganda" and "freely produced art" will be much blurrier. Artists are generally going to be grateful for expanded and ever-expanding opportunities to be expressive, and therefore will tend to be supportive of the regime. But by and large they will still have their pride in their independence and unique personal visions, and audiences are going to respect and encourage that. The more fanatical and less imaginative Party leaders might insist on both acts of gross censorship and fostering anvilicious, heavy handed Message pieces, but they will be better advised to trust to the free vision of artists to write their propaganda for them, because the American audience is going to be richly nourished with a diet of creative work, and will judge what they see accordingly. They will be more forgiving of low production values than of poor creative elements--though production values are themselves a kind of creative element and will be appreciated too.
After the war, when the UASR and its sphere of western hemisphere allies have a chance to "sprawl out" and relax a bit (despite the looming threat of nuclear Ragnarok) I think government propaganda will face ever more difficult hurdles, if we assume it must be tone deaf to the artistic sensibilities of the age, for the art, I have argued before, will go hog-wild. Postwar the Western Hemisphere will be richer than any society in history, much as the USA was OTL, but the wealth is both greater I think, and anyway surely more widely and evenly distributed, meaning that much productivity will be diverted to "superstructural" stuff that people like, such as many kinds of art including cinema in general and cartoons in particular; this was already true during the stretched and anxious '30s and would be more true in the 1950s and later. Having had a solid generation or so of working under Communist conditions to shake things out, artists will be numerous, well funded, and bold; lame hackwork will die on the vine and simple self-respect will maintain some very high standards. In this context--as Meyer or one of those other Hollywood moguls of OTL said, "If you gotta message, see Western Union!" He was of course focused just on box office returns; in the ATL, the artists will have loads of messages of their own; the way to get a good propaganda piece for Party or state messaging would be to identify and cultivate an artist who already is sympathetic and spontaneously producing work consonant with the message, and approach them with proposals and trust them to produce the desired product.
So yes of course, just as in all societies OTL, the UASR is going to produce some propaganda--and by and large it will be better than OTL though surely the early years will produce some tone-deaf hackwork too. But the people of the western Comintern are going to become more and more discerning and critical and demanding of high quality, and to successfully propagandize them, it is necessary to make works that have artistic merit and integrity in their own right. If the message is openly being pushed by the authorities, who are willing to claim credit and blame, it still will be judged by how clever it is.
You spoke of "the Comintern" as a whole, as if there is not a serious rupture between the Western and Soviet forms of it; I gather that the author is moving in the direction of earlier and more thorough reconciliation of Eastern and western Blocs and a truly unified Comintern that never ruptures completely and is rewoven and extended. But clearly the Stalinist approach would be different than the American. Postwar, I gather that neo-Stalinist reaction never had the ability to crush the pro-American sensibility spread by personal contact with millions of Yankee troops aiding on the Eastern front, and that like a virus (from the point of view of Stalinist would-be controllers) assertive independence in the context of socialist integration would spread; factories and towns and regions would defy central command on specific points while telegraphing they would comply on others and thus get away with it as doubt spreads within the Party and army that harsh repression is always the necessary response; gradually over time Party apparatchiks are held accountable, are replaced with more willingly accountable selections of a Party coming under stronger grassroots control and with democratic centralism broadening the tether of acceptable ranges of faction to make the USSR more and more truly democratic. While this is going on the economic effectiveness of the Soviet production system improves as American approaches are adopted piecemeal. Over time then the USSR morphs from the Stalinist tyranny familiar to our OTL history towards a more American kind of freedom. It remains distinctly Russian I suppose, and perhaps will always be more conservative than the Western Hemisphere.
As this applies to art, though, I expect a gradual morphing from OTL standards (which themselves, I understand, did not fail to produce some seriously admirable cinematic art on its own terms from time to time) to more and more freedom and logistic support for more and more numerous artists, who will be engaging in political polemics in their films, but with a rising premium on doing it cleverly, with integrity to the story the film tells--indeed the stories will often be inspired by political polemics. Factions will duel with each other on the screen, with product and counterproduct; cinema is part of the democratic deliberative process. Same is true in UASR too, though the "Don't Tread On Me!" aspect of American political character might insist on a certain range of light entertainment and seriously arty but not very political stuff so that cinema and TV is not all politics all the time 24-7--in Russia the utilitarian principle might prevail more strongly with shaming of those who seek mere escape--but at the same time the deep Russian respect for culture as such will insist that political points go toward those who convey their message most artistically. My guess is that Russian cinema tends to remain "heavier" for longer, with Russians learning English or Spanish a lot to peruse American fare when they just want to relax; Stalin did this OTL (not learning English well, but he did enjoy screening Hollywood fare, so I have heard).
By the present era I gather the morphing of the Soviet branch of the Comintern bloc as a whole into Western Hemisphere broad values and standards has largely been completed, at least to the point that Russians and Americans no longer feel they have severe ruptures of values between them--Russians may continue to look down on Americans as frivolous, and Americans at Russians as uptight cultural conservatives, but Americans will no longer perceive Russians as under heavy handed dictatorship nor will Russians fear American radicalism as a cloak of either mad tyranny or the corruption of revolutionary values portending counterrevolution. It becomes one bloc, and, language barriers permitting, art moves fluidly from one branch to the other and back. Americans watch Soviet media (some in translation, many in the original Russian; perhaps other language groups of the USSR will gain enough cultural cachet that Americans start learning yet other Soviet languages) and Soviet citizens will either learn English and/or Spanish, or have translations, to see Western stuff from UASR and Latin America.
For cartoons to survive in a culturally rich environment like this, they had better have quality and integrity of some kind!
Cartoons in particular seem easier to cross the cultural divide between America and the Soviet bloc too; it is a matter of redubbing the sound track to produce a translation after all.