Final answer:
President Kennedy characterized his era with the concept of a 'new frontier,' representing hope for domestic reforms and confronting Communism globally, all while promoting youthful optimism and national service.
Step-by-step explanation:
President John F. Kennedy argued that the age he was poised to lead was characterized by a new frontier, a term that embodied the nation's aspirations and ideological battles during the 1960s. The new frontier concept proposed by Kennedy emphasized reform and progress, intending to address domestic issues such as poverty, civil rights, and equality, while also challenging Americans to support the United States' endeavors in countering global threats like Communism, particularly in regions like Cuba and Vietnam. His presidency brought a fresh wave of youthful vigor and optimism, as well as an appeal for Americans to participate actively in their nation's politics and governance.