Psychology also explains generational differences among voters’ reactions to two candidates in their late 70s. Older voters seek Mr. Biden’s continuity while youths seek Mr. Sanders’s change.

Carol Goldberg

New York

The writer is a psychologist.

To the Editor:

Can the Democratic Party afford to lose its left wing? Until Tuesday, I was planning to vote for A.B.T. (Anyone But Trump) come November. But the Democratic establishment’s rush to derail Bernie Sanders’s campaign is making me think twice.

I do not know what Pete Buttigieg and Amy Klobuchar were offered in exchange for their endorsement of Joe Biden. Cabinet positions would be my best guess. This smells very bad and is very discouraging to those of us who wish to steer our party in what we believe to be the right direction.

The establishment may think we have nowhere else to go, but that would be wrong. I voted Green Party when, for example, I could not stomach supporting Gore-Lieberman in 2000. I am perfectly ready to do that again.

Please do not take us for granted.

Irvin Cemil Schick

Newton, Mass.

To the Editor:

This country was built on the backs of black enslaved Africans. Now it is their descendants who are exercising their franchise to save our democracy.

Cathryn Cushing

Portland, Ore.

To the Editor:

Re “5 Takeaways From a Super Tuesday That Changed the Democratic Race” (nytimes.com, March 3):

Perhaps the most striking takeaway is the utter failure of the massive amounts of money spent by Michael Bloomberg to have a discernible impact on the Super Tuesday outcome. Over the years, the obsessive quest for campaign contributions by candidates and elected officials on both sides of the aisle and at all levels of our political system has increasingly undermined public confidence in our government. Thank you, Michael Bloomberg, for opening our eyes and teaching us all this profoundly important lesson.

Paul Jellinek

Mercerville, N.J.

To the Editor:

It seems that the Democratic race has come down to two elderly men, one with a history of heart trouble and the other who may be having more and more trouble keeping his mind from wandering. Democrats, and all voters, have the right to know all they can about the health of these candidates. The public should demand that Bernie Sanders and Joe Biden have complete physical and psychological workups, and that the full results be released.