By Reuters  The Senate impeachment trial on whether to remove US President Donald Trump from office formally began on Thursday even as a congressional watchdog found that the White House broke the law by withholding security aid for Ukraine approved by Congress. Chief Justice of the United States John Roberts swears in senators during the procedural start of the Senate impeachment trial of US President Donald Trump in this frame grab from video shot in the Senate Chamber at the US Capitol in Washington, US, January 16, 2020. (REUTERS/US Senate TV/Handout via Reuters / MANILA BULLETIN) The assessment from the nonpartisan Government Accountability Office (GAO) was a setback for Trump, but it was unclear if it would figure in his trial in the Republican-led Senate given that key questions such as whether witnesses will testify or new evidence will be considered remain unanswered. Democrat Adam Schiff, who heads a team of seven House of Representatives members who will serve as prosecutors, appeared on the Senate floor to read the two charges passed by the House on Dec. 18 that accused Trump of abuse of power and obstruction of Congress arising from his dealings with Ukraine. Chief Justice John Roberts, wearing his black judicial robe, took an oath to preside over the trial and then swore in the assembled senators who will serve as jurors. Roberts instructed them to raise their right hand, asking, “Do you solemnly swear that in all things appertaining to the trial of the impeachment of Donald John Trump, president of the United States, now pending you will do impartial justice according to the Constitution and laws, so help you God?” The 99 senators present signed their assent one by one. One senator - Republican Jim Inhofe - was in his home state of Oklahoma to be with a family member facing a medical issue, according to his office, but was due to sign next week. The Senate is expected to acquit Trump, as none of its 53 Republicans has voiced support for removing him, a step that requires a two-thirds majority. Trump has denied wrongdoing and has called the impeachment process a sham. Opening statements were due to start on Tuesday. The abuse of power cited in the House articles of impeachment included Trump’s withholding of $391 million in security aid for Ukraine, a move Democrats have said was aimed at pressuring Kiev into investigating political rival Joe Biden, the president’s possible opponent in the Nov. 3 US election. Congress had approved the funds to help Ukraine combat Russia-backed separatists. The money was ultimately provided in September after the controversy had spilled into public view. “Faithful execution of the law does not permit the President to substitute his own policy priorities for those that Congress has enacted into law,” the GAO said on Thursday, referring to the fact that Congress had voted to appropriate the funds. The GAO’s findings are not legally binding, but its reports are seen by lawmakers as objective, reliable and generally uncontested. It has no prosecutorial power. A pivotal event leading to the impeachment was a July 25 call in which he asked Ukraine’s president to investigate Biden and his son Hunter over unsubstantiated allegations of corruption and to look into a discredited theory promoted by Trump’s allies that Ukraine, not Russia, interfered in the 2016 US election. Democratic Senator Chris Van Hollen, who sought the GAO investigation, said the findings undercut Republican claims that there was nothing wrong with Trump’s action. “The GAO is an independent, nonpartisan entity calling the balls and strikes as they see them,” he told Reuters. “Republican senators and the administration may try to dismiss it. But we now have a clear, lucid finding that the Trump administration violated the law and we know that the president ordered the administration to commit an illegal act.”

WITNESSES OR NO WITNESSES

This is only the third impeachment trial in US history and no president has been removed as a direct result of the process. Richard Nixon resigned in 1974 before the full House could vote to impeach him. The House impeached Andrew Johnson in 1868 and Bill Clinton in 1998, but the Senate did not convict them. Crucial to how long the trial lasts is whether the Senate will consider new evidence and hear from witnesses, support for which is divided largely along party lines, though some Republican senators seemed open to the idea on Thursday. Democratic House Speaker Nancy Pelosi told a news conference the GAO’s conclusion “reinforces - again - the need for documents and eyewitnesses in the Senate.” Schiff indicated that the House prosecutors are considering calling Lev Parnas, an associate of Trump’s personal lawyer Rudy Giuliani, if the Senate permits testimony in the trial. Giuliani has said Parnas, a Ukraine-born US citizen, helped him in investigating the Bidens. Documents released this week indicate Parnas was also involved in monitoring the movements of former ambassador to Ukraine Marie Yovanovitch before Trump removed her in May. In an interview with MSNBC aired on Wednesday, Parnas said he was acting on Trump’s directions: “President Trump knew exactly what was going on. He was aware of all of my movements.” An arm of Congress, the GAO is viewed as a top auditing agency for the federal government that advises lawmakers and various government entities on how taxpayer dollars are spent. Its report said that the US Constitution does not grant a president unilateral authority to withhold funds in the way that Trump did. Instead, a president has a “strictly circumscribed authority” to withhold spending only in limited circumstances expressly provided by law. Holding up money for a policy reason, which the Trump administration did in this case, is not permitted, the report said. Republican Senator John Cornyn said that while there may have been a civil violation of the law, it was not a criminal matter and certainly not an impeachable act. “The Constitution says you impeach presidents for treason, bribery, and high crimes and misdemeanors. And it’s none of those things,” said Cornyn, a former judge, after taking the oath. “That’s what it is, a civil violation of the Impoundment Act,” Cornyn added, mentioning the relevant federal law.