Answer:
The central idea of the excerpt is the President's obligation to address the Congress about the state of the Union and the need to recommend measures for their consideration, especially in relation to the crisis between the United States and Spain due to the warfare in Cuba. The excerpt highlights the connection of the Cuban issue with the country's traditional policy and the adverse effects of the previous similar revolts on American trade, commerce, citizens, and moral values.
To make his speech more effective, the author could have included more vivid and emotional language to generate greater public support for his position, such as appeals to patriotism and justice. Additionally, he could have provided more specific details about the nature of the conflict in Cuba and its impact on U.S. interests, as well as more concrete proposals for resolving the crisis.