Which of the following BEST explains why President Lyndon Johnson, subsequent to President Kennedy’s assassination, did not have the support of a vice president?

When Kennedy was assassinated, Vice President Johnson became president, leaving the vice presidency vacant. At that time, the Constitution had no procedure for appointing a replacement vice president, so the office stayed vacant until the next election. The 25th Amendment, which later established a process for filling a vacancy, was not ratified until 1967, so choice D is incorrect.

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