Through its own internal feuding, then, the SP [Socialist Party] exhausted itself forever and further reduced labor radicalism…to the position of marginality and insignificance from which it has never recovered. The story is a sad but also a chastening one for those who, more than half a century after socialism’s decline, still wish to change America.
…if the history of Local New York shows anything, it is that American radicals cannot afford to become their own worst enemies. In unity lies their only hope.
As Fitton says, “Do we really need a Supreme Court Justice who once lamented the lack of unity on the part of the Socialist Party?”
Judicial Watch had a link to Kagan’s thesis but it doesn’t work as of today. Her senior thesis is consistent with other historical studies in showing that the Socialist Party in New York in the early 20th century was a Jewish phenomenon. She notes that Jews were the backbone of the Socialist Party and that other ethnic groups, such as the Irish and Italians, could not be motivated to join even though they were in a similar economic situation.
Not only were Jews the backbone of the Socialist Party, socialism was very mainstream within the Jewish community. Her account parallels those of other historians who describe the Jewish community from 1890 to 1920 as “one big radical debating society” (see here, p. 71ff).
From  on Jewish districts in New York and elsewhere were famous for their radical voting habits. The Lower East Side repeatedly picked as its congressman Meyer London, the only New York Socialist ever to be elected to Congress. And many Socialists went to the State Assembly in Albany from Jewish districts. In the 1917 mayoralty campaign in New York City, the Socialist and anti-war candidacy of Morris Hillquit was supported by the most authoritative voices of the Jewish Lower East Side: The United Hebrew Trades, the International Ladies’ Garment Workers’ Union, and most importantly, the very popular Yiddish Daily Forward. This was the period in which extreme radicals—like Alexander Berkman and Emma Goldman—were giants in the Jewish community, and when almost all the Jewish giants—among them Abraham Cahan, Morris Hillquit, and the young Morris R. Cohen—were radicals. Even Samuel Gompers, when speaking before Jewish audiences, felt it necessary to use radical phrases.
The result was a radical mainstream Jewish culture that persisted in New York and elsewhere into the 1960s and beyond. With the success of the Bolshevik Revolution, many Jews opted out of the Socialist Party, resulting in a Jewish Communist subculture that was also entirely mainstream within the Jewish community.
Kagan’s comments in her thesis suggest a sympathy with this radical Jewish culture — even a desire to carry it to fruition. Everything we know about her indicates that she continues to be immersed in a Jewish culture whose attitudes are well to the left of the American mainstream–a subculture that was hostile to the traditional people and culture of the US and has now become a hostile elite.
This fits well with Kagan’s childhood in New York’s Upper West Side — described by Dan Freedman as “as conservative’s worst nightmare.” During her college years she wrote, “Where I grew up _ on Manhattan’s Upper West Side _ nobody ever admitted to voting for Republicans.”
Elena Kagan and many of this culture’s children emerged from the Upper West Side political cauldron as committed to making the world a better place for all, mindful that everyday people can affect change as teachers, doctors, lawyers _ and, yes, even journalists _ and make government work for the common good.
There is no indication that Kagan has changed her views, and there’s not much doubt that indeed she will be a judicial activist on the left. Fitton quotes from her Oxford thesis:
As men and as participants in American life, judges will have opinions, prejudices, values. Perhaps most important, judges will have goals. And because this is so, judges will often try to mold and steer the law in order to promote certain ethical values and achieve certain social ends. Such activity is not necessarily wrong or invalid.