Opinion | Biden is right. We’re still fighting a battle for the soul of America.

As the president acknowledged in his three-minute video, winning that fight will require more than beating Mr. Trump a second time. So much has happened since 2020. He highlighted the rollback of abortion rights, the banning of books and laws making it more difficult to vote. “Around the country, MAGA extremists are lining up to take on those bedrock freedoms,” Mr. Biden said. This theme, road-tested during the 2022 midterms, will be potent whether Republicans nominate Mr. Trump or Florida Gov. Ron DeSantis.

But if he is to prove to voters that he is the antidote to extremism, Mr. Biden will also have to use the power of the office he holds to build upon his notable bipartisan achievements, including the infrastructure law, the Chips Act and the modernization of the Electoral Count Act. That task is now much harder with a GOP-led House. A big test looms in the coming weeks, in which Mr. Biden faces a debt-ceiling standoff with Congress.

It was notable that, in his announcement, Mr. Biden referred to “freedom” purely in a domestic context and made no mention of another challenge — leading the Western alliance’s muscular response against Russia’s aggression in Ukraine. The largest land war in Europe since World War II is a historic exemplar of the principles he’s laying out. Mr. Trump and Mr. DeSantis have expressed a desire to curtail support for the Ukrainian forces. Elections are rarely decided on foreign policy, but the president would be wise to tout his global leadership in the fight for democracy — and the contrast with the isolationist bent of his opponents.

The nation’s first octogenarian president will be dogged, of course, by the question of his age. “Watch me,” Mr. Biden says whenever asked about it. And Americans will. He could address their concerns head-on by making himself more available for interviews, news conferences and give-and-take sessions with voters.

Though it is tempting for any sitting president to rely upon a Rose Garden strategy — and campaigning largely from his Delaware basement worked amid the pandemic in 2020 — Mr. Biden could demonstrate his vitality by traveling across the country, touting his achievements and drawing sharp distinctions between the MAGA agenda and his own.

More than most, this election will be a referendum on who we are — and who we want to be — as Americans. “I know we’re good and decent people,” Mr. Biden said in the video. “I know we’re still a country that believes in honesty and respect and treating each other with dignity.” The question is whether our tattered politics can still live up to those ideals.