Donald Trump shocked the world — and even some of his own campaign staffers — one year ago when he defeated Hillary Clinton to become the 45th president of the United States.

The 12 months since then have been tumultuous, as Trump has shaken up Washington politics by breaking long-held norms, dramatically reversing Obama-era policies and making rookie political mistakes that turn into cable news drama.

As he approached the end of his first year in office, Trump’s approval ratings were abysmal — one poll had him at 37%, lower than any president’s approval rating at the same time in over seven decades.

His campaign also faces a major investigation from special counsel Robert Mueller, with one former adviser pleading guilty to lying to investigators and his former campaign manager and another former official facing indictments on other charges. (They have pleaded not guilty.)

But a lot can happen in four years; to be sure, other presidents have bounced back from scandals and mistakes to win re-election. Trump points to the confirmation of Supreme Court Justice Neil Gorsuch, the rollback of various Obama regulations, the U.S. exit from the Trans-Pacific Partnership and the Paris climate deal and a looming tax reform proposal as wins.

TIME has taken a look at the news of the last year since Trump was elected, and determined these moments the most consequential since he became America’s 45th president.

Michael Flynn’s meeting with Sergey Kislyak

One of most important meetings of Trump’s presidential transition period didn’t come to light until months later. In February 2017, the Washington Post reported that Michael Flynn, whom Trump had nominated just days after his election to serve as his National Security Advisor, had met with Russian Ambassador Sergey Kislyak in Dec. 2016 and discussed sanctions against the country, despite statements to the contrary from Vice President-elect Mike Pence.

The report had spiraling implications, not just for Flynn, who would resign from his position shortly afterwards, but for Trump’s entire Administration, which now has multiple investigations into possible campaign collusion with Russia looming over it.

James Comey being fired and the subsequent appointment of Robert Mueller as Special Counsel

Trump unexpectedly announced on May 9 that he was firing then-FBI Director James Comey, citing recommendations from the top-ranking officials at the Department of Justice that disapproved of the way Comey had handled its investigation into Clinton’s emails.

While Trump was technically within his jurisdiction to fire Comey, the public reaction was one of skepticism, not only because the President had praised Comey for the way he handled that very investigation, but because Comey had publicly acknowledged he was overseeing the FBI’s investigation into possible collusion between Trump’s campaign and Russia.

Just days after Comey was fired, Trump admitted the Russia investigation was a key factor in his decision to terminate him from his top spot at the FBI during an interview with NBC News’ Lester Holt. That revelation heightened concerns that Comey’s replacement would halt the Russia investigation — and intensified calls for the appointment of a special counsel.

Those calls were answered about a week later. On May 17, Deputy Attorney General Rod Rosenstein announced he was appointing former FBI Director Robert Mueller as special counsel to lead the investigation into Russian interference in the 2016 election. The announcement came one day after a New York Times report that said Trump had asked Comey to stop an investigation into his former National Security Adviser Michael Flynn.

Withdrawing from the Paris agreement

After much anticipation, Trump announced in the White House Rose Garden on June 1 that he intended to withdraw the United States from the Paris Climate Accord, arguing that the withdrawal would pave the way for more domestic job creation. (Trump did, however, leave open the possibility of renegotiations that would benefit the U.S.). “I was elected to represent the citizens of Pittsburgh, not Paris,” he said in his speech.

The announcement meant that, once the withdrawal became official, the United States would be the only country aside from Nicaragua and Syria not to join the agreement. (Both countries have since said they would sign the global climate pact, leaving the U.S. as the only U.N. member country not to sign it.) The decision, which came in spite of pressure from global leaders and members of his own administration, was not only a major step in dismantling his predecessor’s legacy, but showcased the lengths to which Trump would go to appease his voter base. He had said throughout the campaign that he would leave the Paris agreement should he become president.

Announcing a ban on transgender military members

On July 26, Trump issued an unexpected announcement on Twitter.

“After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow…Transgender individuals to serve in any capacity in the U.S. Military,” he wrote. “Our military must be focused on decisive and overwhelming………victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail. Thank you.”

Trump’s announcement immediately provoked an outcry from his critics and the LGBTQ community. But action was somewhat slow to occur. The Pentagon did not respond to Trump’s tweets about this issue, but waited for official guidance from the White House to reverse the decision to allow transgender soldiers to serve in the military, which took another month. This guidance provided a six-month time frame to develop a plan for transgender soldiers currently serving, which Secretary of Defense James Mattis announced he would take advantage of while he convenes a panel to develop further assessments.

But transgender members of the military also sued Trump in court, and a federal judge rejected the ban on Oct. 30, dealing another blow to the policy’s feasibility.

The Senate’s failure to repeal the Affordable Care Act

Both Trump and nearly every Congressional Republican up for reelection ran on the idea of repealing and replacing the Affordable Care Act, former President Obama’s signature health care overhaul. So it was no surprise that the House of Representatives immediately got to work on legislation that would accomplish this objective. What was more surprising was their inability to pass it.

Although the House managed to narrowly pass a version of a health care reform bill in May, it needed to advance in the Senate if it was ever going to reach Trump’s desk. It didn’t. With 52 Republican lawmakers in the chamber, party leadership could only afford two defections. Maine Senator Susan Collins and Alaska Senator Lisa Murkowski were firmly in the opposition camp, and Arizona Senator John McCain officially killed any hope of the bill’s passage with a surprise “no” vote in the middle of the night on July 28.

While the three defectors were hailed as heroes by Democrats and anyone else who opposed the bill (including a slew of celebrities), it also showcased the Trump Administration’s limited power over Congress. McCain, who has a long history of feuding with President Trump that dates back to the President deriding him for his military captivity during the 2016 campaign, made his decision despite pleas from Vice President Mike Pence, who had come to Capitol Hill that night to ensure the legislation passed. And Murkowski maintained her opposition to the bill even after Trump criticized her on Twitter, and after Interior Secretary Ryan Zinke reportedly threatened to withhold funding for Alaska.

Cutting a deal on the debt ceiling with Chuck Schumer and Nancy Pelosi

On Sept. 6, Trump agreed to a deal with House Minority Leader Nancy Pelosi and Senate Minority Leader Chuck Schumer that would raise the debt ceiling for three months while providing $15.3 billion in aid to the victims of Hurricane Harvey, which struck Texas and Louisiana in August. Trump, Schumer and Pelosi reached the deal on Sept. 6, and Trump signed it into law after both chambers had approved it.

The necessity of providing aid to the victims of Hurricane Harvey undoubtedly sped up the legislative process, and Trump still faced opposition to the bill from his own party. But nevertheless, it seemed that the author of “The Art of the Deal” had finally achieved this objective in Washington D.C. — and in a bipartisan fashion.

Mueller indictments and George Papadopoulos pleads guilty

On Oct. 30, nearly six months after Mueller was appointed to serve as Special Counsel, Trump’s former campaign manager Paul Manafort and Manafort’s longtime associate Rick Gates were indicted on charges of money laundering, failing to register as foreign agents and failing to report their foreign bank accounts. Mueller’s office also revealed that day that George Papadapoulos, a onetime foreign policy adviser to the Trump campaign, had pleaded guilty to lying to the FBI about a conversation he had with a Russian professor who has links to the Kremlin.

Both Trump and the White House reacted to these developments by downplaying Manafort and Papadopoulos’ roles in the campaign, and highlighting that most of the charges detailed in the indictment against Manafort happened before he joined the campaign. (“There is NO COLLUSION!” Trump wrote on Twitter that day).

But the charges, while they may not have spelled out collusion, signified that this investigation that has dogged Trump since his presidency started is not stopping anytime soon.

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Write to Alana Abramson at Alana.Abramson@time.com.