Hillary Rodham Clinton is a former U.S. senator, secretary of state and Democratic nominee for president in 2016.

Wednesday’s attack on the Capitol was the tragically predictable result of white-supremacist grievances fueled by President Trump. But his departure from office, whether immediately or on Jan. 20, will not solve the deeper problems exposed by this episode. What happened is cause for grief and outrage. It should not be cause for shock. What were too often passed off as the rantings of an unfortunate but temporary figure in public life are, in reality, part of something much bigger. That is the challenge that confronts us all.

Over these last days, I’ve thought about my experiences as a senator from New York on Sept. 11, 2001, and the 9/11 Commission Report that followed. The report’s authors explored the failures that opened the door for a devastating terrorist attack. “The most important failure,” they wrote, “was one of imagination. We do not believe leaders understood the gravity of the threat.”

Almost 20 years later, we are living through another failure of imagination — the failure to account for the damage that can be done to our nation by a president who incites violence, congressional leaders who fan the flames, and social media platforms that sear conspiracy theories into the minds of Trump’s supporters. Unless we confront the threats we face, we risk ensuring that last week’s events are only a prelude to an even greater tragedy.

Trump ran for president on a vision of America where whiteness is valued at the expense of everything else. In the White House, he gave white supremacists, members of the extreme right and conspiracy theorists their most powerful platforms yet, even claiming that there were “very fine people” among the torch-wielding militia members who converged on Charlottesville in 2017.

By the time he lost in 2020, he had whipped a dangerous element of our country into a frenzy. His supporters began planning their insurrection, making plans to march on the Capitol and “stop the steal.” Members of Congress, including Sen. Josh Hawley (R-Mo.), Sen. Ted Cruz (R-Tex.) and Rep. Mo Brooks (R-Ala.), encouraged them, in Brooks’s words, to “start taking down names and kicking ass.” Trump left no doubt about his wishes, in the lead-up to Jan. 6 and with his incendiary words before his mob descended.

So how do we move forward as a country? What does it say about us that so many were complicit, while those who sounded the alarm were dismissed as hysterical?

The generous explanation is that it’s hard to comprehend the danger of what seem like ridiculous conspiracy theories until you experienced that danger firsthand. This is a lesson I’ve learned myself. I’ve had my share of unpleasant experiences with people who believed I was evil incarnate — everything from being burned in effigy for fighting for health-care reform, to claiming that I was running a pedophilia ring out of a pizza parlor, to receiving a mail bomb from a rabid Trump cult member.

Fanatical ideas can lead to real, even deadly harm. That’s something the people of Michigan realized last year when armed militia members plotted to kidnap their governor. It’s something Nashvillians saw when a conspiracy theorist blew up an entire city block. Now, it’s something all of America has experienced.

But it is not enough to scrutinize — and prosecute — the domestic terrorists who attacked our Capitol. We all need to do some soul-searching of our own.

In Isabel Wilkerson’s new book “Caste,” she cites a question from historian Taylor Branch: “If people were given the choice between democracy and whiteness, how many would choose whiteness?” Wednesday reminded us of an ugly truth: There are some Americans, more than many want to admit, who would choose whiteness.

It’s sobering that many people were unsurprised by what occurred last week, particularly people of color, for whom a violent mob waving Confederate flags and hanging nooses is a familiar sight in American history. Consider what we saw last June, when Black Lives Matter protesters peacefully demonstrating in Lafayette Square were met with federal officers and tear gas. If the first step toward healing and unity is honesty, that starts with recognizing that this is indeed part of who we are.

Removing Trump from office is essential, and I believe he should be impeached. Members of Congress who joined him in subverting our democracy should resign, and those who conspired with the domestic terrorists should be expelled immediately. But that alone won’t remove white supremacy and extremism from America. There are changes elected leaders should pursue immediately, including advocating new criminal laws at the state and federal levels that hold white supremacists accountable and tracking the activities of extremists such as those who breached the Capitol. Twitter and other companies made the right decision to stop Trump from using their platforms, but they will have to do more to stop the spread of violent speech and conspiracy theories.

The Biden administration will need to address this crisis in all its complexity and breadth, including holding technology platforms accountable, prosecuting all who broke our laws, and making public more intelligence and analysis about domestic terrorism.

Despite the horror of what we saw happen, in the weeks and months ahead the news cycle will move on. We owe it to ourselves not to do the same. We have the strength, the ability and — yes — the imagination to confront what happened and ensure that nothing like it ever happens again. That’s what real patriotism looks like.

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