About a year ago, I got into a discussion with a group of friends my age about our parents, the cohort famously christened “the greatest generation” by journalist Tom Brokaw in his 1998 book of the same title. The gist of the conversation was that where our parents struggled to overcome economic depression and war, we’ve only known prosperity and peace.

“We’ve never been tested,” one of my friends observed.

His words rang so true. When I look back on my 60-plus years, it’s as if my generation — or at least the part of it that grew up white, male and middle class after the Second World War — has lived in a bubble. We have been immune from history, our only challenge, seemingly, the pursuit of ever-greater pleasures.

But I, for one, inherited enough of my parents’ worry genes to harbour the uneasy feeling that we might face a reckoning someday. I’ve always wondered what it would look like if history came calling, and whether we’d have the grit to respond to it when it did.

The bomb that went off with the election of Donald Trump was also the sound of a bubble bursting. I and my contemporaries shared the shock and alarm that millions of others felt. But it was also tinged with a sense of loss: our free ride was over. We were being tested, finally.

The new U.S. president and the people around him bear a marked resemblance in tone and substance to the totalitarian regimes our parents fought in their own generation. The first months of Trump’s presidency — a nightmare of rash, mean-spirited executive orders; spiteful tweets; scandals; incoherent, bellicose press conferences; and deeply worrisome national-security moves — confirmed beyond doubt that the gravity of the Oval Office would not restrain the new president but rather inflame him.

Now that history has caught up with us, privileged boomers must find common cause with marginalized groups who have been tested all their lives, and for whom Trump represents a dangerous escalation. The end goal must be stopping him and his cronies before they can inflict irreparable damage to liberal democracy. At a minimum, this means using the courts, political pressure and diplomatic sway to isolate and contain the president until his term ends. But the best outcome is outright defeat. This likely means marshalling enough legal, political and moral suasion to convince Republican members of Congress that their own interests are better served with Trump out of the picture.

This is a fight for everyone, not just Americans. Joining the battle can be as simple as sending a cheque to the American Civil Liberties Union or subscribing to the media voices that are calling Trump to account. It goes without saying that we must resist Trump copycats here in Canada.

The upsurge of protest since Trump’s inauguration is encouraging. But it’s just a start. In the coming months, the movement needs to refine an ethically framed message that speaks to a full spectrum of decent-minded people, including those on the soft edges of Trump Nation. The movement must also sharpen its objectives — for example, insist that Congress force Trump to disclose his tax returns — and develop leaders around which it can coalesce.

The struggle needs as many recruits as it can muster, but the onus is especially on people of my vintage. We have lived well off the fruits of liberal democracy. Now that it is imperilled, we, in particular, must rise in its defence.

This story originally appeared in the April 2017 issue of The Observer as part of the regular column “Observations.”