By James Oliphant and Simon Lewis
ATLANTA (Reuters) - Democratic White House contenders backed the impeachment inquiry of Republican President Donald Trump during a debate on Wednesday, saying his efforts to press Ukraine to investigate former Vice President Joe Biden was an example of the administration's corruption.
"We have to establish the principle that no one is above the law, we have a constitutional responsibility and we need to meet it," said U.S. Senator Elizabeth Warren, an early supporter of Trump's impeachment.
At the fifth debate in the Democratic race to pick a challenger to Trump in the November 2020 election, the candidates said the president's conduct had forced lawmakers to hold him accountable.
"The constitutional process of impeachment should be beyond politics and it’s not part of the campaign. But the president’s conduct is," said Pete Buttigieg, mayor of South Bend, Indiana.
The Democratic-led House of Representatives has launched an impeachment inquiry into Trump's bid to get Ukraine to investigate Biden and his son Hunter, who served on the board of Ukrainian gas company Burisma. It is also looking into whether Trump may have withheld $391 million in security aid to help Ukraine fight Russian-backed separatists as a way to pressure Kiev to undertake the investigations.
Trump has denied doing anything wrong, and accused Biden of corruption without offering evidence. Biden also has denied any wrongdoing and said Trump's efforts showed he was worried about having to face him in the 2020 election.
A U.S. diplomat said on Wednesday that "everyone was in the loop" about a Trump administration effort to get Ukraine to carry out investigations that might ultimately benefit Trump, including Vice President Mike Pence and Secretary of State Mike Pompeo.
The Democratic debate comes just 11 weeks before the first nominating contest in Iowa, on Feb. 3, raising the stakes for the 10 participants hoping for a chance to make an impression with voters before time runs out.
The Democratic White House race has featured a three-way battle at the top of recent national polls between moderate Biden, the former U.S. vice president, and progressive leaders Warren and U.S. Senator Bernie Sanders.
But Buttigieg has taken the lead in two recent polls in Iowa and is on the move in early-voting New Hampshire despite questions about his relative lack of experience and his inability to make inroads with African-American voters.
Warren has seen some of her momentum fade after coming under fire in the last debate from rivals who questioned how she would pay for her government-run Medicare for All plan, which would eliminate private health insurance, without raising taxes on the middle class.
The field of debaters has been trimmed from the 12 candidates in last month's Democratic debate. Former U.S. Representative Beto O'Rourke of Texas dropped out of the race and former U.S. Housing Secretary Julian Castro was cut from the stage by the Democratic National Committee's toughened qualifying criteria.
The debaters also could face questions about two other people who will not be on the stage - Deval Patrick, the former Massachusetts governor who jumped into the race last week, and former New York Mayor Michael Bloomberg, who is pondering a run because he is unsure if any of the current candidates can beat Trump.