To the Editor:

Re “Bolton’s Account Fuels Senate Push to Call Witnesses” (front page, Jan. 28):

Let’s do some simple math here. John Bolton’s “tell all” manuscript was provided to the White House on Dec. 30. The members of the legal team representing this president were certain to have either read it or were briefed upon its contents, yet weeks later they marched into the Senate trial and continued along their merry way lying in front of the entire nation.

Are there four G.O.P. senators with a spine?

Steve Himmelman

Chicago

To the Editor:

When I read that “a handful of Republicans appeared to be moving closer to joining Democrats in a vote to subpoena Mr. Bolton,” I cannot help but wonder what would happen if a large bloc of Republican senators chose not to march in lock step with everything Trump. We keep hearing about four possible Republicans who might breach the barriers. Where are those others who reportedly have contempt for President Trump? Could Mr. Trump and Mitch McConnell inflict damage on, say, 20 or more senators?

There is an Ethiopian proverb that states, “When spiders unite, they can tie down a lion.”

Sandra Allik

Cambridge, Mass.

To the Editor:

Re “John Roberts Can Call Witnesses to Trump’s Trial. Will He?,” by Neal K. Katyal, Joshua A. Geltzer and Mickey Edwards (Op-Ed, nytimes.com, Jan. 27):

If Chief Justice John Roberts can call witnesses in the impeachment trial, rather than calling John Bolton, why not call Donald Trump to the witness stand?