As lawmakers trickled into the US House of Representatives Wednesday to debate the impeachment of Donald Trump, the congresswoman who gaveled in the session felt the full weight of history upon her shoulders.

"Of course I was nervous," House Democrat Diana DeGette told AFP just outside the chamber, after presiding over the opening hours of debate on whether to charge Trump with abuse of power and obstruction of Congress.

US Speaker of the House Nancy Pelosi brought the chamber to a standstill when she launched the debate on the impeachment of President Donald Trump
US Speaker of the House Nancy Pelosi brought the chamber to a standstill when she launched the debate on the impeachment of President Donald Trump AFP / Saul LOEB

"It's a big responsibility, it's sobering, and I think the members feel that way too."

Throughout a grave and fateful opening session, more than 400 lawmakers came face to face with their ultimate responsibility beyond sending US soldiers into battle: voting on whether to impeach a president.

Republicans fiercely opposed to the Democratic effort threw up roadblocks to slow the process, but to no avail. It churned toward an evening vote in which the chamber's Democratic majority was expected to approve two articles of impeachment.

The push to impeach President Donald Trump has exposed the depth of the partisan divide in Washington and beyond
The push to impeach President Donald Trump has exposed the depth of the partisan divide in Washington and beyond GETTY IMAGES NORTH AMERICA / Sarah Silbiger

Early in the day, some signs of normalcy and bipartisan decorum were still visible.

Al Green, a House Democrat who first filed articles of impeachment against Trump back in 2017, collegially stood next to rival Republicans as they recited the Pledge of Allegiance.

Trump supporters -- like these singing Christmas carols in Washington on December 18, 2019 -- decry the "partisan" nature of the impeachment
Trump supporters -- like these singing Christmas carols in Washington on December 18, 2019 -- decry the "partisan" nature of the impeachment AFP / Olivier Douliery

Freshman Republican Dan Crenshaw, a military veteran wounded in Afghanistan, made a point of shaking hands with Democrats.

But the mood soon stiffened.

Faces froze as a clerk began reading House Resolution 755: "Resolved, that Donald John Trump, president of the United States, is impeached for high crimes and misdemeanors."

IMAGESAs the sun begins to set over Capitol Hill, US lawmakers careen toward the brink of one of the most divisive and momentous political steps in years: the impeachment of President Donald Trump for abuse of power and obstruction of Congress.
IMAGESAs the sun begins to set over Capitol Hill, US lawmakers careen toward the brink of one of the most divisive and momentous political steps in years: the impeachment of President Donald Trump for abuse of power and obstruction of Congress. AFPTV / Eleonore SENS
The US impeachment vote in the House of Representatives and the Senate
The US impeachment vote in the House of Representatives and the Senate AFP / Gal ROMA

Nancy Pelosi, the speaker of the House who launched the impeachment inquiry nearly three months ago, struck a solemn figure, clad in a sober black suit, as she launched the debate.

Passions built up quickly.

"There is no proof -- none! -- that the president has committed an impeachable offense," boomed Republican congresswoman Debbie Lesko, her voice rising.

Her colleagues seethed over "pure partisan politics" and the impeachment "sham" bringing shame on the House.

And Republican Barry Loudermilk invoked religious imagery one week before Christmas, by saying that "Pontius Pilate afforded more rights to Jesus than the Democrats have afforded this president."

"We do not hate Donald Trump," House Judiciary Committee chairman Jerry Nadler said later, drawing laughter from the Republican side.

The push to impeach Trump has exposed the depth of the partisan divide in Washington and beyond.

Most Republicans were absent from the chamber during key moments of the debate. At one point it appeared that fewer than 25 of the 197 House Republicans were in attendance. Democrats often fared little better.

At the back of the chamber, a lonely figure: Justin Amash, the conservative who left the Republican Party to become an independent after declaring he believed Trump is unfit for office.

Largely ignored by members of his former party, Amash was soon in animated conversation with Alexandria Ocasio-Cortez, the fiery and popular liberal first-time congresswoman.

But he said he felt sad for Republicans, many of whom he counts as friends, because "they see and hear no evil when it comes to this president."

"I feel a certain sense of relief that this is finally coming to a head, and a sense of humility that I'm here."