Julian Zelizer is a history and public affairs professor at Princeton University and the author of " The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society ." He's also the co-host of the " Politics & Polls " podcast. The opinions expressed in this commentary are his own.

(CNN) This has been a crazy year in American politics, perhaps the most tumultuous year since 1968. When, in the early morning hours of November 9, the outcome of the 2016 election became clear, almost everyone -- experts and non-experts alike -- felt that the political earth had trembled beneath their feet.

This was one of the most unpredictable elections anybody had ever seen. Donald Trump was anything but a conventional candidate. Facing Hillary Clinton, one of the most experienced candidates in recent history, Trump won despite having no background in politics, ruthlessly defying almost every political tradition, surviving a number of scandals, and as anyone -- like me -- who grew up in the tri-state area in the 1980s remembered, being a notorious troublemaker who craved public attention.

Notwithstanding the shock and awe of the election, nothing could prepare us for what was to come.

If you live in the moment of politics, you no doubt witness the weirdness of US government right now. But if you stand back and look at the cumulative record of the past 12 months, the impact is truly astounding. It is not a surprise that the Washington Post found seven in ten Americans believe that the political divisions in the United States have become as bad as they were during the Vietnam War . Here are thirteen of the most shocking moments since Donald Trump won the election.

1. On November 27, 2016, President Trump tweets that "I won the popular vote if you deduct the millions of people who voted illegally." Trump would continue to make this false claim, including in private conversations. Despite winning the Electoral College and thus the election, Trump clearly has felt stung by the fact that he lost to Hillary Clinton in the popular vote. The tweet revealed his willingness to play with the facts and to make claims in reckless fashion that could have serious policy consequences, not least of which is the controversial "voter fraud commission" Trump established.

2. As he takes office, President Trump refuses to create a clear firewall between his global business empire and the Oval Office. Handing control, but not ownership, of the business to his two sons Eric and Donald in January, President Trump, who has spent most of his weekends at Trump properties in what amounts to an ongoing advertisement, ignores the warnings of ethics watchdogs in both parties who say this situation poses serious problems. The decision establishes the tone at the outset for the muddied ethical landscape of Trump-land.



3. On March 4, President Trump accuses former President Obama of wiretapping him during the campaign in Trump Tower in New York City. The allegation, which then-FBI Director James Comey says is not true, is symptomatic of a President willing to launch all sorts of unwarranted accusations against officials.

4. President Trump fires James Comey on May 9, while the FBI director is in the middle of investigating whether his campaign colluded with the Russians in the election. Trump will say in a meeting with Russian officials on May 10 that he fired Comey to get rid of this "Russia thing" and explains to his guests that firing that "nut job" relieved "great pressure" on him. The decision was part of his aggressive response to the Russia scandal and clearly backfired -- it triggered the appointment of Robert Mueller as special counsel.

5. President Trump tweets about MSNBC host Mika Brzezinski, a leading critic of the administration, on June 29 saying that she was "bleeding badly from a face-lift" at a social gathering in Florida where they schmoozed. The comment reflected his hostile views about women, his continued antagonism with the non-conservative press, and the debased kind of the language that he is willing to use in public.

6. With mounting evidence about how much Russian President Vladimir Putin's regime, a hostile power, worked to intervene in the 2016 election, the President caves to pressure on August 2 to sign legislation passed by a Republican Congress that imposed tighter sanctions on Russia and curtailed his ability to ease them. The legislation grew out of frustration that the administration was indifferent, at best, to how Russia had used hackers and social media to influence the election in favor of the GOP. Congress passed the legislation several weeks after the revelation that Donald Trump Jr. and a number of top campaign officials had met with a Russian lawyer in Trump Tower on June 9 after being promised via email damaging information about Hillary Clinton.

7. At a speech to police cadets on July 28, President Trump effectively endorses police brutality when he says that police officers should not be so worried about people who have been arrested banging their heads as they get into squad cars. "Please don't be too nice," he said. The comments were later described by the White House as a joke , though this didn't sit well with anyone who has been outraged by incidents of shocking police violence against African-Americans over the past few years.



8. On the same day, July 28, Senator John McCain returns to the Senate after being diagnosed with brain cancer to give a dramatic thumbs-down to the Obamacare repeal and replace notion that had been a centerpiece of GOP politics for years. President Trump badly mishandled the legislative process and Senate Majority Leader Mitch McConnell did not prove to be up to the task of leading a majority during a moment of united government. The bill proved deeply unpopular with voters. As he pushes the idea of a big tax cut package, President Trump's legislative record remains meager.



9. President Trump resists making a strong denunciation of white racism, insisting on talking about how " both sides " engage in extremism. Following a horrific day of neo-Nazi marches in Charlottesville, Virginia, to protest the removal of a statue of the Confederate Robert E. Lee, President Trump is slow to come down hard on the protesters. Even after finally making a statement condemning these groups, he then shocks some of his own advisers with a bizarre press conference on August 15 at Trump Tower where he backs away from his unequivocal condemnation of white racists.



10. Amid escalating tensions with North Korea, President Trump on September 19 brings his Twitter banter to one of the most important international institutions that we have. The President turns to juvenile name-calling by referring to Kim Jong Un as "Rocket Man" during his first address to the UN General Assembly. As the world watched anxiously to see if the administration would handle this challenge with a level head, the President decides to use hawkish bluster and an ad-hoc approach in dealing with foreign policy. He threatened that he would " totally destroy " North Korea if he had to.

11. The chairman of the Senate Foreign Relations Committee, Bob Corker, a fellow Republican who supported Trump's campaign, warns in early October that President Trump's statements about foreign leaders threatened to trigger "World War III." Just a handful of presidential advisors, according to Corker , were the only thing that help "separate the country from chaos." Corker also called the White House an "adult day care center." Senator Jeff Flake made a dramatic speech to the Senate: "We must never regard as 'normal' the regular and casual undermining of our democratic norms and ideals." The comments exposed deepening rifts within the GOP about whether President Trump is fit to serve, at the same time that they show how strong partisan loyalty remains. Even with Republicans thinking and saying things like this, there has still been almost no effort within the party to take serious steps to constrain the President.

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12. Trump cannot resist saying something after Congresswoman Frederica Wilson maintains that the President had made insensitive remarks to the pregnant widow of Sgt. La David Johnson . The conversation itself, as well as the back-and-forth that followed, literally brought Myeshia Johnson to tears. This was not the first time that the President tangled with Gold Star families. (After the Democratic convention, he lashed out against the Pakistani-American parents of US Army Captain Humayun Khan for challenging his devotion to the constitution, and for mocking Senator John McCain for having been captured in Vietnam.)

13. Trump's former campaign manager Paul Manafort and his close associate Rick Gates are indicted on a number of major charges that include money laundering. And the nation learns that one of candidate Trump's foreign policy advisors, George Papadopoulos, pled guilty to lying to the FBI about his contacts with Russian officials. Details of the plea reveal he was working in the spring and summer of 2016 to set up contacts between Russian officials and the campaign. At a time the President was working hard to discredit the investigation and focus attention on Hillary Clinton, Americans were reminded of how serious Robert Mueller's investigation is and how long this will likely go on.

Of course, what makes this list so remarkable is just how incomplete it is. Readers will inevitably be able to think of dozens more moments they would include. And we all know that there are many more to come, probably one on the day this piece is published.