Julian Zelizer, a CNN political analyst, is a professor of history and public affairs at Princeton University, and author of the forthcoming book, "Burning Down the House: Newt Gingrich, the Fall of a Speaker, and the Rise of the New Republican Party." The views expressed in this commentary belong to the author. View more opinion at CNN.

(CNN) With another presidential tweet, another high-level adviser bites the dust. John Bolton, President Trump's third national security adviser, won't be coming back. "I informed John Bolton last night that his services are no longer needed at the White House," Trump told the nation Tuesday. Bolton immediately disputed the claim that he was fired, saying that he resigned Monday night.

However it happened, the bigger point is that he is gone.

The turnover in this administration has been stunning and is emblematic of an administration where governance is not a top priority. The Bolton firing is not the last one that we will be experiencing. The only question is whether voters will apply the same logic to President Trump himself come November 2020.

Many of Trump's most ardent critics won't be upset about Bolton's departure. Bolton, one of the neoconservatives from the George W. Bush era who liked to bang the drums of war, is extremely unpopular among Democrats and considered by many a dangerous voice in Washington.

Trump and the America First crowd in the GOP also detested him as a prime example of what went wrong in the early 2000s when Republicans supported George W. Bush's war in Iraq.

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