Which President spoke at the 1968 National Convention?

Richard M. Nixon was the President who spoke at the 1968 National FFA Convention. His participation marked an important moment in FFA history, as it illustrated the organization's significance and relevance at a national level. Nixon's engagement with the FFA highlighted the connection between agriculture, the youth involved in farming, and national policies. His address emphasized themes of leadership, responsibility, and the importance of agriculture in the American economy, which resonated with the values and mission of the FFA.

The other options represent Presidents who did not speak at this particular event. For instance, Lyndon B. Johnson, while a contemporary of Nixon and involved in various agricultural policies, did not attend the convention; similarly, John F. Kennedy's time in office was prior to 1968, and while he was supportive of agricultural initiatives during his presidency, he was not present at this event. Gerald Ford, who took office later, also did not speak at the convention in question. This context further consolidates Nixon's role at the 1968 National Convention as a significant highlight in FFA's history.