While the distinctions between the two are disappearing, the need to use the two descriptions as they relate to the positioning of attribution in a sentence has not. Paraphrase , in its purest sense, improves clarity yet captures tone and mood by using many of the speaker's words.
Reporters choose it when the direct quote has minor flaws that interfere with clarity.
Reported speech is the choice when the reporter decides that the source's ideas can be communicated more clearly and efficiently by reworking large or small portions of what a speaker has said. Despite the distance between Johnson and said, the sentence remains reported speech, so the rule applies. He said he always votes Republican. Not only would that constitute a grammatical error, it also would indicate a condition of perpetual voting behavior, descriptive of the past and predictive of the future. If that were true, others would soon tire of hearing him say it over and over and over.