So if it is Senator Sanders versus Donald Trump in the general election, there is a pretty good chance that Mr. Trump will win. The Russians want four more years of Mr. Trump and will try to rig this election so that it is a Trump-Sanders contest.

Allen Cohen

Santa Barbara, Calif.

To the Editor:

Many thanks to Paul Krugman (column, nytimes.com, Feb. 23), David Leonhardt (column, Feb. 24) and Charles M. Blow for offering advice to Bernie Sanders about enlarging his tent as his campaign rolls on. What a welcome contrast to the articles that assume that most of us agree that Senator Sanders should be stopped somehow.

No matter whom we nominate, that nominee will face a host of smears, disinformation and possibly even criminal mischief from the White House and the G.O.P. The best antidote is to keep up a steady mantra asking what the Trump administration and the Senate as led by Mitch McConnell are doing to keep the Russians and other hackers and bot-makers out of our election.

Anne Mackin

Boston

To the Editor:

I will support and vote for the candidate who says, in his or her opening statement in a debate, something like:

“I will answer questions only about the things I believe in, and the policies I would, if elected, try to carry out regarding such things as the economy, foreign policy, education, immigration, infrastructure, health plans, global warming and gun control.

“I do not intend to waste any time talking about my opponents. If you want to know what they think, ask them. If they choose to attack my agenda, so be it. But if they do so and don’t offer viable alternatives, I don’t think that they are worthy of your support. First question, please.”