IF WORDS alone could unify a nation, the United States would have come together after then-President Donald Trump proclaimed, in his inaugural address four years ago, “The Bible tells us how good and pleasant it is when God’s people live together in unity. . . . When America is united, America is totally unstoppable.” And so, after President Biden’s inaugural address, in which he repeated the word “unity” eight times and portrayed the country as able to accomplish great goals when it acts as one, the public is entitled to ask: Could this time be different?

We would answer skeptics with an emphatic yes. There are many reasons to hope Mr. Biden’s message, delivered with evident passion and no little eloquence, could have real effect. One reason is that, unlike Mr. Trump, he did not contaminate it with rancor about “carnage” and “stolen” jobs, or pit a “righteous” public against an exploitative “establishment.” He instead urged “humility” and asked “those who did not support us” to “hear me out.” Additionally, Mr. Biden approached the inaugural lectern knowing how dangerously Mr. Trump deepened divisions, especially on Jan. 6. His description of democracy as “fragile” was rooted in this experience, which many in his audience lived first-hand. The presence of leading Republicans — former vice president Mike Pence, Sen. Mitch McConnell (Ky.), Rep. Kevin McCarthy (Calif.) and Sen. Roy Blunt (Mo.) — in that audience was a promising sign, more resonant, surely, than the mean-spirited message Mr. Trump sent by not showing up.

And there is the matter of biography. Mr. Biden comes to the presidency not as an overconfident outsider but as someone who learned the meaning of stewardship over a complex body politic through decades in the Senate and eight years in the vice presidency. He has made his share of mistakes, but never that of suggesting that he “alone” could fix this country’s problems. Rather, he has a record of bipartisan cooperation, and he has defended it even against rivals for the Democratic nomination. He converted one such critic, Vice President Harris, into a historic partner — the first woman and first Black person to hold the nation’s second-highest office.

Mr. Biden did not urge unity at the expense of principle, or in service of some bland policy agenda. His welcome reference to the right to dissent and disagree as “perhaps this nation’s greatest strength,” in no way denied that he, too, would fight for what he and those who voted for him believe in, including long-postponed action to stem climate change and uproot systemic racism. He called out white supremacy by name and pledged to “defeat” it. Whereas four years ago, Mr. Trump launched a bizarre lie exaggerating attendance at his ceremony, Mr. Biden demanded adherence to truth.

A final reason to hope: Actions speak louder than words. Four years ago, Mr. Trump repaired from the Capitol to the White House to sign an executive order curtailing Obamacare and, a week later, issued his notorious ban on Syrian refugees as well as travelers from certain Muslim-majority countries. Mr. Biden spent his first day undoing those orders and others, while directing his administration to extend pandemic-crisis protections for renters and student borrowers.

In both tone and substance, this president spent his first day harking back to the serious, responsible traditions of the office. It felt bracingly, refreshingly new.

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