If Joe Biden can’t be the Democratic nominee, who should replace him?

All the president had to accomplish Thursday night was to look and sound strong and convince his party and swing voters he is capable of another four years in office, and at every step he failed.

Mr. Biden says he loves this nation and has spent his whole life defending democracy and there is no doubt this is true. But the time has now come for this valiant soldier to show his true affection for America by stepping aside. There are several Democratic governors — Gavin Newsom of California, Gretchen Whitmer of Michigan and Josh Shapiro of Pennsylvania — who would be strong candidates and real challengers to Mr. Trump.

Henry A. Lowenstein, Newport, R.I.

Wes Moore?

Richard M. Nixon’s resignation from the presidency came about after a group of leading Republicans went to the White House to tell him it was time to go. I’m looking for the same from a group of leading Democrats.

It’s a shame. Who other than President Biden had the personal relationships and knowledge of how to get things done that resulted in his accomplishments on infrastructure, prescription drugs and other issues? No other Democrat or Republican had been able to do so, and no one standing with him on the primary debate stage in 2020 could have done it. But now, Mr. Biden’s determination puts America’s experiment with democracy at risk.

I’m looking for Mr. Biden to step aside and for a cry to go up (it’s already started) for Wes Moore, the governor of Maryland, to announce his candidacy. The country right now needs someone “bigger” than both sides who can forge a sort of national unity, to sweep into office like Barack Obama did. Mr. Moore has the credentials and force of personality to do it. And he comes with no baggage.

Mr. Biden’s poor debate performance was a blessing. It will wake him up and make him realize that even though he was the right man at the right time, his time to go has arrived.

Gary W. Litchfield, Rockville, Md.

Josh Shapiro?

The Democrats have a duty and responsibility to think outside the box and choose a replacement for President Biden. It would show initiative, imagination and a strong sense of responsibility. Mr. Biden must be persuaded to withdraw for the good of the country. Gov. Josh Shapiro of Pennsylvania is a no brainer. He would deliver his state, along with other swing states, denying Donald Trump the presidency.

Paul Schoenbaum, Richmond

Kamala Harris?

We were lucky it was a June debate. President Biden’s pick for vice president can now step up and become the Democratic nominee. And Mr. Biden can now step up and best serve his legacy — and democracy writ large — by supporting her.

Kamala D. Harris has the competency and wherewithal to prosecute and win this campaign. Mr. Biden has supported women throughout his distinguished career. The day he announced his reelection campaign, I sent my first-ever email to the White House communicating my disappointment while making clear I thought he had done a great job as president during his first term. But his legacy and the country were not well-served by running again, a decision that implied he thought he was still the best candidate around, despite his age. He was missing an opportunity to best serve his legacy and the country by paving the way for a woman (finally!) to be president. His endorsement and advice — based on his lifetime of experience and wisdom — could help ensure Ms. Harris becomes our next president.

He can now revisit that opportunity. It’s not too late. He can show up at the Democratic National Convention in Chicago and give his full support to her candidacy. If he does, the Democrats will win and our country will win. And he will have ensured that the country — indeed the world — will remember him in history books with gratitude as the president who paved the way for a woman president and rescued democracy when it hung in the balance.

Mary Offerdahl, Ashburn, Va.

Bernie?

After the first presidential debate, it is clear that President Biden is not up to the job of being president for another four years. Democrats must find a replacement. But let’s not substitute Hillary Clinton for the job. She will not appeal to enough people.

Sen. Bernie Sanders (I-Vt.) has the clarity, energy and vigor of a much younger person. His advocacy of universal health care would appeal to all Americans. His belief in a human-rights-based foreign policy would sit well with the increasing number of Americans who are disaffected by our unqualified support for Israel’s wants.

Another possible candidate would be Dennis J. Kucinich. He has had many years in Congress, is known to Republicans through being a commentator on Fox News and is an excellent campaigner. He has courage and the right values to deal with the pressing issues of our times — climate change, universal health care and the future of democracy itself.

Esther Riley, Ithaca, N.Y.

Jill Biden?

I am a supporter of the lifetime record of President Biden. I believe in his personal roots in working America. I admire his international experience and ability to marshal the friends of the United States to work together for a better world and against aggressive tyranny.

I was pained by Mr. Biden’s struggle in the debate Thursday night to express himself energetically while promoting his record and plans. Among the commentators expressing similar worries, there is a discussion about whether it is too late for him to step aside and find another worthy candidate to oppose the man who couldn’t or wouldn’t remember the truth. Who could have the credibility needed at this late date in the election process?

I write to urge consideration of Jill Biden as the best candidate to step forward and carry on the work of her husband. She is a brilliant woman. She has accompanied her husband for many years in a quiet supportive role. She can credibly carry on Mr. Biden’s work to develop America’s future in a way that builds out from the middle and honors our nation’s leading role in promoting peace, security and care for the needs of our one planetary home.

As president, Ms. Biden would have Mr. Biden’s full support and the benefit of his lifelong experience and wisdom. A Jill Biden-Kamala D. Harris ticket would raise excitement for this team of women to lead our country. We would not lose the momentum and record of the Biden campaign. I believe that these women would be able to break through political logjams caused by U.S. and foreign politicians caring more for their own future than the true needs of people. Let’s nominate and elect Jill Biden as our president.

Robert Graf, Springfield, Va.

Or almost anyone else

Democrats have a deep bench to draw from: Michigan Gov. Gretchen Whitmer, Pennsylvania Gov. Josh Shapiro, Sen. Amy Klobuchar of Minnesota, Maryland Gov. Wes Moore, California Gov. Gavin Newsom, Kentucky Gov. Andy Beshear, Sen. Sherrod Brown of Ohio, Commerce Secretary Gina Raimondo, Michele Obama.

Any one of them would beat Donald Trump, hands down.

David Pederson, Excelsior, Minn.

Joe Biden. Still Joe Biden.

Let’s keep our eye on the ball. The president wasn’t “jacked up.” Donald Trump seemed sedated. But we’re not casting a role; we’re electing a president. Forget presentation and focus on facts. President Biden is still my choice.

Nancy Howard, Ocean City, Md.

Despite a disappointing debate performance, accentuated by a pronounced feeble manner and weak voice, President Biden still demonstrated his experience, integrity and a grasp of issues that affect all Americans.

Donald Trump was undeniably more vigorous. But vitality alone is not a measure of reassurance when it comes to protecting the sovereignty of our nation. Mr. Trump’s widely known character flaws usually detract attention from his ignorance about matters crucial to effective governance. Not this time. His nescience was on full display.

The contrast in competing visions couldn’t have been more clear-cut, but this election isn’t just about dissimilar ideologies. It is about the very survival of the republic. Voters must decide if they want an ill-informed president who favors dismantling the Constitution or one hellbent on doing whatever is necessary to protect it.

Jim Paladino, Tampa