Trump’s defense team ignores the Bolton bombshell.

President Trump’s lawyers avoided on Monday any mention of a newly disclosed firsthand account from his former national security adviser, John R. Bolton, that directly undercuts one of the defense’s main arguments.

The New York Times first reported details from drafts of Mr. Bolton’s upcoming book Sunday night, including Mr. Bolton’s assertion that Mr. Trump said he wanted to continue a freeze on military aid to Ukraine until officials there helped with investigations into Mr. Trump’s political rivals.

Calls for witnesses intensified as a result, and three Republican senators — Mitt Romney of Utah, Lisa Murkowski of Alaska and Susan Collins of Maine — indicated they might vote with Democrats to allow new witnesses to testify at the trial. Democrats need four Republicans for such a measure to pass.

Mr. Romney told reporters on Monday, “I think it’s increasingly likely that other Republicans will join those of us who think we should hear from John Bolton.”