The U.S. House of Representatives on Wednesday will debate articles of impeachment against President Trump for abuse of power and obstruction of Congress over his dealings with Ukraine. Earlier in the day, the House voted to approve rules for the vote.
The two articles of impeachment are certain to pass in the House, where Democrats hold a firm majority.
"He gave us no choice", said Pelosi, launching debate in the House of Representatives on impeaching the U.S. leader.
"It is tragic that the president's reckless actions make impeachment necessary", she said.
McCarthy's motion failed, and debate began shortly thereafter.
Despite days of testimony from USA officials who told lawmakers of the Trump administration's efforts to pressure Ukraine for domestic political purposes, Americans are still nearly exactly evenly split on whether to remove Trump from office.
What remains unclear is whether the months-long partisan drama will have any effect on the 2020 election beyond giving Trump reasons to boast of having beaten back Democratic efforts to remove him.
The articles of impeachment accuse Trump of abusing power and obstructing justice, charges that House Democrats say fall under the umbrella of "high crimes and misdemeanours" for which a United States president can be impeached.
"Very sadly, the facts have made clear that the President abused his power for his own personal, political benefit and that he obstructed Congress", Ms Pelosi told her party colleagues. Five of them are USA senators who will act as jurors in the impeachment trial. Republicans are framing the impeachment proceedings as politically motivated and unfair. "History will judge us by whether we keep intact that fragile republic handed down to us by our forebears over 200 years ago - or whether we allow it to be changed forever".
Removing Trump from office would require a two-thirds majority of those present and voting in the 100-member chamber, meaning Democrats would have to persuade at least 20 Republicans to join with them to end Trump's presidency.