Why did some isolationists feel that there was no need for Americans to feel threatened by
developments in Europe and Asia?

Most isolationists felt that there was no need for americans to feel threatened by developments in Europe and Asia because the vast pacific and atlantic oceans insulated the country from troubles in those regions, and the United States had formed friendly alliances with all the other nations in the Western hemisphere.

explanation:

diaspora, (greek: dispersion)hebrew galut (exile), the dispersion of jews among the gentiles after the babylonian exile; or the aggregate of jews or jewish communities scattered “in exile” outside palestine or present-day israel. although the term refers to the physical dispersal of jews throughout the world, it also carries religious, philosophical, political, and eschatological connotations, inasmuch as the jews perceive a special relationship between the land of israel and themselves. interpretations of this relationship range from the messianic hope of traditional judaism for the eventual “ingathering of the exiles” to the view of reform judaism that the dispersal of the jews was providentially arranged by god to foster pure monotheism throughout the world.

the first significant jewish diaspora was the result of the babylonian exile (q.v.) of 586 bc. after the babylonians conquered the kingdom of judah, part of the jewish population was deported into slavery. although cyrus the great, the persian conqueror of babylonia, permitted the jews to return to their homeland in 538 bc, part of the jewish community voluntarily remained behind.

the largest, most significant, and culturally most creative jewish diaspora in early jewish history flourished in alexandria, where, in the 1st century bc, 40 percent of the population was jewish. around the 1st century ad, an estimated 5,000,000 jews lived outside palestine, about four-fifths of them within the roman empire, but they looked to palestine as the centre of their religious and cultural life. diaspora jews thus far outnumbered the jews in palestine even before the destruction of jerusalem in ad 70. thereafter, the chief centres of judaism shifted from country to country (e.g., babylonia, persia, spain, france, germany, poland, russia, and the united states), and jewish communities gradually adopted distinctive languages, rituals, and cultures, some submerging themselves in non-jewish environments more completely than others. while some lived in peace, others became victims of violent anti-semitism.