Senators – including three key Republicans – began peppering House Democrats and Donald Trump's legal team with questions in his impeachment trial about his motives towards Ukraine and the bar the prosecution's case must clear to remove him from office.

The three GOP politicians, who will have a major say in the shape of the trial, showed some of their cards right off the bat after another day of questioning, with one of Mr Trump's attorneys telling them the premise of their query should lead them to acquit the president.

Democratic senators need four Republicans to vote with them to force votes on witnesses, with Maine's Susan Collins, Alaska's Lisa Murkowski and Utah's Mitt Romney on the list of GOP members who have yet to signal their plans.

They got the question-and-answer period, which could last for 18 hours over two days, off to a quick start.

Ms Collins read a joint question aloud, the first time a senator not named Mitch McConnell or Chuck Schumer – the majority and minority leaders – had spoken into a microphone inside the chamber in over a week.

She asked Mr Trump's counsel whether, if the president had more than one motive in his actions towards Ukraine, could he be convicted? The crux of the inquiry was this: if part of his motive was acting in the interests of the United States and/or over worries about giving American monies to a corrupt government, should senators vote to acquit on the abuse of power article?

All the president's lawyers: The team fighting Trump's impeachment Show all 6 1 /6 All the president's lawyers: The team fighting Trump's impeachment All the president's lawyers: The team fighting Trump's impeachment Alan Dershowitz Dershowitz is a controversial American lawyer best known for the high-profile clients he has successfully defended. Those clients have included OJ Simpson, Jeffrey Epstein and Harvey Weinstein. One longtime Harvard Law associated told the New Yorker Dershowitz "revels in taking positions that ultimately are not just controversial but pretty close to indefensible." Getty All the president's lawyers: The team fighting Trump's impeachment Ken Starr Starr became a household name in the 1990s as the independent counsel who led the investigation that led to Bill Clinton's impeachment. That investigation began as a look into a real estate scandal known as Whitewater, and eventually led to impeachment after Mr Clinton lied under oath about having an affair with White House intern Monica Lewinsky. AP All the president's lawyers: The team fighting Trump's impeachment Jay Sekulow Sekulow is the president's longtime personal attorney, and, now, personal lawyer in the White House. He has been accused by former Rudy Giuliani associate Lev Parnas of being "in the loop" during the Ukraine scandal. Getty All the president's lawyers: The team fighting Trump's impeachment Pam Bondi Bondi is the former attorney general in Florida, and a longtime backer of the president's. She made a name for herself in Florida for taking hyper partisan stances on issues, and her penchant for publicity. She is likely to be a prominent public-facing figure during the trial. AFP/Getty All the president's lawyers: The team fighting Trump's impeachment Pat Cipollone Cipollone is the White House counsel, and leading the president's defence team. Getty All the president's lawyers: The team fighting Trump's impeachment Rudy Giuliani While not officially named as one of the president's impeachment lawyers, it is hard to ignore Giuliani's outsized role in this process. The former mayor of New York has been making headlines for months as he defends his client, and for his apparent role in the effort to compel Ukraine to launch the investigation into Joe Biden. We'll see how he figures in the actual trial, which he has said he would like to be a part of. Reuters

About such a "mixed motive," Patrick Philbin, deputy White House counsel, replied one "couldn't possibly be the basis for an impeachable offence".

He pointed to a House Democratic-prepared report about its impeachment inquiry, saying the Judiciary Committee Democrats established a standard for their case – for themselves – in which they had to prove Mr Trump was asking Ukraine's government to announce a "sham" probe of the Bidens and there was "not a scintilla" of evidence "to look into" about then-vice president Joe Biden and son Hunter Biden's business dealings there.

"That's a very demanding standard they've set themselves to meet," Mr Philbin said, noting that Obama administration officials raised concerns about Joe Biden's anti-corruption work in Ukraine while his son sat on the board of an under-investigation energy firm there. "And that means their case absolutely fails."

Collins and Murkowski later jointly asked another question. But it was also not about calling witnesses, though they did seek information from the president's legal team about whether Mr Trump ever expressed worry about corruption in Ukraine before Joe Biden announced his 2020 presidential campaign.

Mr Philbin was unable to say more than that Mr Trump spoke to senior Ukrainian officials about general corruption there. Notably, John Bolton, the former White House national security adviser whose coming book stating he heard Mr Trump link military aid to Ukraine probes of Mr Biden, could provide first-hand knowledge about that matter if the Senate called him as witness.



Texas Senator Ted Cruz, a Republican who once harshly clashed with Mr Trump, asked the president's legal team if it matters whether Mr Trump was after a quid pro quo with Ukraine.

Alan Dershowitz, a celebrity Harvard University professor working on Mr Trump's legal team, replied – again, defying many in his own profession – that such an action by a president only would be impeachable if the quid pro itself contained an illegal action. "If the president does something, in the public interest, that he thinks might help him get elected," Mr Dershowtiz told senators, the action would not be unlawful or meet the Constitution's impeachment standard.

Tennessee Senator Marsha Blackburn and a handful of other Republicans asked Mr Trump's team about whether the standard for impeachment by the House is lower than that senators should use when considering whether to convict and remove a sitting commander in chief.

Mr Philbin fielded the question, saying the Senate has a higher standard to consider than the House, returning to the defence team's week-long argument that Mr Trump committed no crimes. That means he cannot be impeached, he said, because the Constitution links impeachment to criminal actions. It is unclear if that argument, however, will sway any Democrats to vote with Republicans for an acquittal because their legal theory has been debunked by many legal scholars.

The first day of questioning began with a cloud hanging over the proceeding – will four GOP senators join Democrats later this week on whether to call witnesses, setting up a longer trial than Mr Trump would like and a possible legal battle.

Mr Schumer told reporters, minutes before the trial resumed, that he is "hopeful" he can pick off four Republicans, but he said he views the task still as an "uphill fight". Not showing his cards, he merely described his side as "still in the ballpark" on calling witnesses.

The New York Democrat denied Republican warnings that bringing in witnesses would drag the trial on for months – especially if the question of whether Mr Trump can invoke executive privilege to block testimony heads to the courts.