The primary contradiction centers on imperialism. It is better if the US is less outwardly violent and they includes components of consciousness and of ability to coherently push for its imperialist interests. Socialists in the US should seek to spread anti-imperialist and socialist sentiment through growing their organizations and lobbying other organizations via coalitions and by partaking in action. Socialists in the US should not naively build trade unionism, as it easily blows back on this entire project. Instead, socialists should focus on key sectors. For example, there are self-proclaimed socialists that actively try to work with weapons manufacturers because they have a union and that is supposedly the socialist thing to want. It's no surprise that these same people don't even try to organize anything against their employers. Also, please consider being strategic in your audience. Many socialists join unions and try to lobby staff or think they will take over the union with some lazy anti-staff rhetoric. Both of these tactics fail. Staff in unions are (usually) promoted through loyalty and can be shitlibs and reactionary. Taking over a union is a years-long project that requires a cadre and a reasonable goal for how you will sustain your numbers given that there are not enough socialists to keep all the leadership positions socialist.

In terms of the question of division, the people living in the United States have never been united. The United States was founded on genocide and slavery and the genocide targets and enslaved were not fans of this arrangement. Racial and gender discriminating were the norm and still mostly are. There are large disenfranchised labor underclasses, primarily prison labor and undocumented immigrant labor, both of which are massively exploited. The capitalist ruling class of the United States built racialized slavery in response to worker demands and has never left behind this successful divide-and-conquer strategy, using every social movement to hide the material underpinnings of who is fighting in favor of oppression and why they are so well-resourced. The US has a massive population of cops with military equipment. Etc etc etc etc.

The concept that the US is more divided now is a false consciousness that erases past struggles. It's based mostly on bourgeois electoral analysis that says the two capitalist parties vote more along party lines now. Big whup, they're just fighting over different bourgeois factions' interests and the culture wars they directly maintain to keep your focus away from their material basis and the only tool we have to oppose them: community organization. It's the red vs blue divide and as we see repeatedly that is a charade.