To be marxist in the States

what does it means to be marxists in the United States? I mean: USA is the most important capitalist superpower and the small communist party has always seen like a terrible threat by common people.
In Italy we've got a long-time communist tradition (from 1921) and the Italian Communist Party was the second party until the nineties. I know that the situation is totally different in the U.S.A.

I'd like to know your impressions, experiences and opinions.

PS: excuse me for my english

American socialism (scientific and utopian alike) was at its zenith at the beginning of the 20th century. The Socialist Party of America alone managed to get two congressmen and 70 mayors elected and received nearly 1 million votes during the presidential elections of 1912 and 1920; even smaller parties like the Socialist Labor Party were able to amass the support of tens of thousands of workers; and the Industrial Workers of the World could boast of a membership of approximately 40,000 individuals in 1923. Alas, the First and Second Red Scares caused immeasurable harm to movement for working class emancipation in the United States, and a combination of New Deal reformism and post-war economic growth significantly extinguished radical sentiments within the proletariat.

Nevertheless, one cannot help but conclude that the New Left's contribution to radicalism in North America (i.e., prioritizing fringe identity politics over traditional class struggle) is one of the chief factors in explaining why the United States currently possesses the weakest labor movements in the developed world. The nation's ethnocultural heterogeneity additionally places it at a relative disadvantage in terms of organizing, as Friedrich Engels explained:

". . . .Then, and more especially, immigration, which divides the workers into two groups [in the United States]: the native-born and foreigners, and the latter in turn into (1) the Irish, (2) the Germans, (3) the many small groups, each of which understands only itself: Czechs, Poles, Italians, Scandinavians, etc. And then the Negroes. To form a single party out of these requires quite unusually powerful incentives. Often there is a sudden violent élan, but the bourgeois need only wait passively, and the dissimilar elements of the working class fall apart again."
Engels's 1893 letter to Friedrich Sorge quoted in Science and Society, Vol. II, No. 3 (1938).

Of course, the various European populations Engels cited have since been assimilated into American society and the working class is fragmented more along racial lines today, e.g., mestizo and Amerindian immigrants together with African Americans on one end, and European Americans on the other. But the nation's ethnocultural heterogeneity doesn't represent an insurmountable obstacle, in my opinion. A contemporary movement which eschews fringe identity politics and elevates class struggle as its primary concern could achieve appreciable results, if intelligently executed.

As far as my subjective experiences are concerned, I've noticed a marked generational gap. Baby boomers (i.e., individuals born between 1946 and 1964) maintain a skeptical attitude toward socialist rhetoric—due, in no small part, to the Second Red Scare campaign and a quaint belief in the attainability of the so-called "American dream"—while Generation X'ers and Millennials are vastly more open-minded when it comes to considering anti-capitalist ideas. Terms such as "Marxist" and "communist" continue to evoke fear even younger generations of workers due to their association with 'Stalinism' and authoritarianism, but I suspect this too will diminish with time.