The Sentence Diagram Generator will visually represent the grammatical structure of the sentence: "After an unsuccessful meeting that he had with John C. Calhoun, one of the most influential senators in the nation, Joseph realized that he was wasting his time in Washington and departed for home."

1. Main Clause: Joseph realized

   • Subordinate Clause: that he was wasting his time in Washington
   • Coordinating Clause: and departed for home

2. Prepositional Phrase: After an unsuccessful meeting

   • Relative Clause: that he had with John C. Calhoun
   • Noun Phrase: one of the most influential senators in the nation

The diagram will illustrate these relationships, showing the main clause, subordinate clauses, and prepositional phrases in a structured format.