WASHINGTON (AP) — Senate Majority Leader Mitch McConnell abruptly backed offsome of his proposed rules for President Donald Trump’s impeachment trial on Tuesday, easing plans for a tight two-day schedule and agreeing that House evidence will be included. He acted after protests from senators, including fellow Republicans.

The trial quickly burst into a partisan fight at the Capitol as the president’s lawyers opened arguments in support of McConnell’s plan. Democrats objected loudly to his initial rules, and some Republicans then made their concerns known in private at a GOP lunch.

Without comment, the Republican leader submitted an amended proposal after meeting behind closed doors with his senators as the trial opened. The handwritten changes would add an extra day for each side’s opening arguments and stipulate that evidence from the Democratic House’s impeachment hearings be included in the record.

There is still deep disagreement about calling additional witnesses.

“It’s time to start with this trial,” said White House Counsel Pat Cipollone, the president’s lead lawyer in brief remarks as the proceedings opened in public.

Chief Justice John Roberts gaveled open the session, senators having taken an oath last week to do “impartial justice” as jurors. House prosecutors were on one side, Trump’s team on the other, in the well of the Senate, as senators sat silent at their desks, no cellphones or other electronics allowed.

Senators were stunned by McConnell’s shift, which came during the private lunch and briefly delayed the start of the historic session.

A spokeswoman for Republican Sen. Susan Collins said that she and others had raised concerns. The Maine senator sees the changes as significant improvements, said spokeswoman Annie Clark.

Collins, Sen. Rob Portman of Ohio and a substantial number of other Republicans from across the party’s ideological spectrum wanted to make the changes, according to two people familiar with the matter but unauthorized to discuss it in public. Some argued that the two-day limitation would have helped Democrats cast Republicans as squeezing testimony through in the dead of night.

The turnaround was a swift lesson as White House’s wishes run into the reality of the Senate. The White House wanted a session crammed into a shorter period to both expedite the trial and shift more of the proceedings into late night, according to a person familiar with the matter but unauthorized to discuss it in public.

“READ THE TRANSCRIPTS!” the president tweeted from overseas miles away, as he returned to his hotel at a global leaders conference in Davos, Switzerland.

That’s the transcript of his phone call in which he asked new Ukrainian President Volodymyr Zelenskiy for “a favor.” A whistleblower’s complaint led the House to impeach Trump on a charge of abuse of power for pushing Ukraine to investigate Democratic rival Joe Biden and his son Hunter Biden as the White House was withholding military aid from the U.S. ally at war with bordering Russia. The Democrats cite that transcript as solid evidence against Trump, though he repeatedly describes it as “perfect.”

Senate Democratic leader Chuck Schumer of New York was to offer the first amendment to the rules — a proposal to issue a subpoena to the White House for “all documents, communications and other records” relating to the Ukraine matter.

It seeks records about Trump’s orders to hold off military aid to Ukraine, along with White House communications about any investigations it wanted about the Bidens. In a vote later Tuesday, it was likely to be rejected by Republicans.

Democrats had warned that the rules package from Trump’s ally, the Senate GOP leader, could force midnight sessions that would keep most Americans in the dark and create a sham proceeding.