Presidents are forever linked to their most memorable lines or slogans, phrases that become inseparable from their passage through history. Ronald Reagan proclaimed morning in America. Barack Obama promised America hope and change. Donald Trump pledged to make America great again. Our leaders also utter words they might rather take back — say, about lip-reading or the meaning of “is” — but their go-to lines can capture their message, signal their attitude and even betray their worldview.

Joe Biden has long settled on his preferred pitch. “We are living through a battle for the soul of this nation,” he wrote in 2017, after the darkness of Charlottesville. Biden highlighted the battle for that soul again in his 2020 and 2024 campaign announcements and has revisited it in multiple speeches. It is ominous and a bit vague — John Anzalone, Biden’s 2020 pollster, complained during that race that no one knows what “soul of America” means and that the line “doesn’t move the needle.” But it does provide the rationale for Biden’s candidacy and presidency. Under Trump, Biden contends, America was becoming something other than itself.

Yet there is another Biden line — a single word, really — that also stands out, and it comes up whenever this president reflects on that American soul, on what the country is and what it might become. It is still.

“We have to show the world America is still a beacon of light,” Biden wrote in that same post-Charlottesville essay.

“We have to prove democracy still works — that our government still works and we can deliver for our people,” he said in a speech to a joint session of Congress in April 2021.

“We are still an America that believes in honesty and decency and respect for others, patriotism, liberty, justice for all, hope, possibilities,” the president said in a speech in September at Independence Hall in Philadelphia, where he asserted that the foundations of the Republic were under assault by MAGA forces. “We are still, at our core, a democracy.”

There is an insistent quality, almost a stubbornness, to Biden’s “still.” Its implicit assumption is that many Americans may no longer believe in the nation’s professed virtues or trust that they will last much longer, that we must be persuaded of either their value or their endurance. To say that America is a democracy is to issue a statement of belief. To say that we are still a democracy is to engage in an argument, to acknowledge — and push back against — mounting concerns to the contrary.

The contrast between Biden saying America is still a democracy and Trump vowing to make it great again is more than a quirk of speechwriting. What presidents say — especially what they grow comfortable repeating — can reveal their underlying beliefs and basic impulses, shaping their administrations in ways that are concrete, not just rhetorical. Biden’s “still” stresses durability; Trump’s “again” revels in discontinuity. “Still” is about holding on to something good that may be slipping away; “again” is about bringing back something better that was wrested away. Both candidates, now in a dead heat in the 2024 presidential race, look to the nation’s past but through divergent lenses. It’s the difference between America as an ideal worth preserving and an illusion worth summoning.

Biden’s use of “still” is both soothing and alarming. It connotes permanence but warns of fragility. The message of “still” is that we remain who we are, but that this condition is not immutable, that America as Biden envisions it exists somewhere between reality and possibility. “If we do our duty in 2022 and beyond,” Biden said ahead of the midterm elections last year, “then ages still to come will say we — all of us here — we kept the faith. We preserved democracy. We heeded not our worst instincts but our better angels. And we proved that for all its imperfections, America is still the beacon to the world.”

Remember, it’s only when things are wretched that presidents reach for Lincoln. In good times, no one gives a damn about our better angels.

Americans do recognize the threat to our system of government, but they just don’t seem that energized by the dangers. A New York Times/Siena College poll last fall found that more than 70 percent regarded American democracy as being at risk, but only 7 percent thought that was the nation’s most important problem. Biden’s message demands that we care. “Democracy is hard work,” the president said at a Summit for Democracy meeting in March.

In that speech, Biden also indulged in a bit of a victory lap. “Here in the United States, we’ve demonstrated that our democracy can still do big things and deliver important progress for working Americans,” he said, citing lower prescription-drug costs, new infrastructure investments, electoral reform and his administration’s efforts against climate change. It was an answer to Biden’s speech before Congress two years earlier, when he said we had to prove that democracy still functions. “It’s working,” he told the summit. “It’s working.”

But three months later, after the Supreme Court declared affirmative action in college admissions unconstitutional, the president reiterated his concern that the basic American promise of equal opportunity remains unfulfilled. “The truth is — we all know it,” he stated. “Discrimination still exists in America. Discrimination still exists in America. Discrimination still exists in America.” That third and final still was especially vociferous.

Even as Biden affirms what he believes we still are, he also reminds us of all he believes we still must do — his “still” entails duty along with reassurance. The president can declare, as he did in 2021, that “it’s never ever, been a good bet to bet against America, and it still isn’t,” but the need to state it so emphatically acknowledges that the stakes are rising, and that the odds are not improving.

Over the years, Biden has offered varying visions about what America still means to him. In his 2007 memoir, “Promises to Keep,” he reflected on the nation’s ability to inspire the globe after a visit to a refugee camp in Chad. “We sometimes forget that America is the one country in the world that still shimmers, like that ‘shining city on the hill,’ as a promise of a brighter tomorrow,” he wrote. But in Evan Osnos’s 2020 book, “Joe Biden: The Life, the Run and What Matters Now,” Biden considered a different vision of what America still is. “Watching [George] Floyd’s face pinned against that curb and his nose being crushed, I mean, the vividness of it was, like, ‘Holy God. That still happens today?’”

Biden’s “still” was once a contrast to the plight of other countries; now it is about competing visions of our own.

In Jon Meacham’s 2018 book, “The Soul of America,” that presidential biographer and Biden wordsmith points to the “universal American inconsistency” of upholding rights and freedoms for some but not others. “The only way to make sense of this eternal struggle,” Meacham concludes, “is to understand that it is just that: an eternal struggle.”

At times, Biden seems torn over whether the struggle is eternal or temporary. In his 2017 essay on the battle for the soul of the nation, he noted that charlatans and political con artists “have long dotted our history,” invariably blaming immigrants for our troubles and capitalizing on the hopelessness and despair of struggling communities. But in the video launching his 2020 campaign, he expressed confidence that history will deem Trump an “aberrant moment” in the national timeline, and only if Trump was granted eight years in the White House would he “forever and fundamentally” transform the national character. In other words, vote for Biden and America would still be America.

Of course, Biden didn’t say Trump would need eight consecutive years to remake the nation; two nonconsecutive terms could prove even more definitive. That would mean that we tried Trump, attempted an alternative, and then decided we wanted him back after all. It would mean we chose Trump, again.