A second day of opening arguments by Donald Trump’s defense at his impeachment trial in the US Senate has concluded.

Here are six key takeaways:

John who?

On Sunday night, a blockbuster report emerged that the former national security adviser John Bolton’s forthcoming book says Trump told Bolton that he did not want to send aid to Ukraine until Ukraine delivered the goods on Joe Biden.

On Monday, Trump’s defense team responded to the attack on the heart of their case by … wholly ignoring it. With a minor exception, neither Bolton’s name nor the substance of his book’s reported charge came up in about seven hours of trial on Monday.

“They seem to be operating in a bubble of denial,” said Senator Richard Blumenthal, a Connecticut Democrat, “and I think they are fast losing any shred of credibility by essentially ignoring the evidence, from John Bolton or others.

“They’re saying there isn’t enough evidence, but they’re trying to stop it from coming before the Senate.”

Will there be witnesses?

The key question remained: would the Bolton news, or anything else, convince a small group of Republicans to side with Democrats and call witnesses at the trial? One Republican senator who had not previously spoken publicly on the topic, Pat Toomey of Pennsylvania, told colleagues they might have to consider a one-for-one witness exchange with Democrats.

The vote on whether to call witnesses is expected to be held on Friday. If it fails, the Senate was expected to acquit Trump immediately. If, on the other hand, witnesses are called, the trial would move into less predictable territory.

Hunter Biden in the spotlight

Instead of talking about John Bolton, Trump’s defense team advanced arguments they hoped senators would find more urgent. One member of the team, Pam Bondi, the former Florida attorney general, spoke for an hour about corruption inside the Ukrainian gas company Burisma, and the lack of qualifications Hunter Biden, the former vice-president’s son, had to sit on the company’s board.

Charging out of the chamber for a dinner break after the speech, the Republican Ted Cruz of Texas said his mind was made up: “If the Senate later this week ... decides to go down the road on additional witnesses,” he said, “the most important witness for the Senate to hear from is Hunter Biden.”

The patchwork defense

While Trump’s team did spend some time defending the president’s actions, saying he was concerned about corruption in Ukraine and about burden-sharing with Europe, the defense team spent the majority of the day on seemingly peripheral questions.

One lawyer rose to deliver an hour-long speech praising Rudy Giuliani’s conduct in Ukraine as Trump’s personal lawyer. Another examined Hunter Biden’s career in Ukraine, and a third delivered a critique of the House managers’ case that found time for a takedown of a New York Times series about the advent of slavery in the United States.

Starr and Dershowitz

The Trump team trotted out two star lawyers: Alan Dershowitz, the well-known civil liberties litigator and erstwhile Jeffrey Epstein sidekick; and Kenneth Starr, the former independent counsel during Bill Clinton’s impeachment. Both men argued that impeachment must be grounded in a criminal offense, a view not shared by mainstream scholars and in any case diminished in its relevancy by imputations of criminality to Trump.

Starr, quaintly, argued that the United States was suffering from a surfeit of impeachment.

“The Senate is being called to sit as the high court of impeachment all too frequently,” said Starr, who bears unique responsibility for the single previous presidential impeachment trial in the last 150 years.

Saying the quiet part out loud