WASHINGTON — The House is plunging into a landmark impeachment week, with Democrats who once hoped to sway Republicans now facing the prospect of an ever-hardening partisan split over the question of removing President Donald Trump from office.

Lawmakers were getting their first look at the House Intelligence Committee’s impeachment report Monday night behind closed doors. The findings are expected to forcefully make the Democrats’ case that Trump engaged in what Chairman Adam Schiff calls impeachable “wrongdoing and misconduct” in pressuring Ukraine to investigate Democrats and Joe Biden while withholding military aid to the ally.

For Republicans offering an early rebuttal ahead of the report’s public release, the proceedings are simply a “hoax,” with Trump insisting he did nothing wrong and his GOP allies in line behind him. Trump tweeted his daily complaints about it all and then added a suggestive, if impractical, question: “Can we go to Supreme Court to stop?”

With the Judiciary Committee set to launch its first hearing Wednesday, the impeachment proceedings are presenting a historic test of political judgment in a case that is dividing Congress and the country.

Departing for a NATO meeting in London, Trump criticized the House for pushing forward Monday with proceedings while he was heading overseas.

He predicted Republicans would actually benefit from the entire impeachment effort against him, though “it’s a disgrace for our country.”

For the Democrats, House Speaker Nancy Pelosi faces a critical moment of her leadership as she steers the process ahead after resisting the impeachment inquiry through the summer.

Speaking to reporters at the international climate conference in Madrid, Pelosi declined to engage with impeachment questions. “When we travel abroad, we don’t talk about the president in a negative way,” she said. “We save that for home.”

Possible grounds for impeachment are focused on whether Trump abused his office as he pressed Ukrainian President Volodymyr Zelenskiy in a July 25 phone call to launch investigations into Trump’s political rivals. At the time, Trump was withholding $400 million in military aid, jeopardizing key support as Ukraine faced an aggressive Russia at its border.

The report, which the Intelligence panel will vote on Tuesday and make public, also is expected to include evidence the Democrats say suggests obstruction of Congress, based on Trump’s instructions for his administration to defy subpoenas for documents and testimony.

The next step comes when the Judiciary Committee gavels open its own hearing with legal experts to assess the findings and consider potential articles of impeachment ahead of a possible vote by the full House by Christmas.