Critical vote on impeachment this week.

WASHINGTON >> The House plans to take its first formal vote Thursday on the impeachment inquiry into President Donald Trump, Democratic leaders said Monday, ushering in a new phase as they prepare to go public with their investigation into his dealings with Ukraine.

Democrats described the vote, which will come more than a month after they launched the inquiry, as a necessary next step to lay out the rules for conducting it in public, rather than a response to accusations from Republicans and the White House that the process has violated precedents and denied the president due process rights.

Speaker Nancy Pelosi announced the vote in a letter to colleagues Monday afternoon.

The rules will also allow for staff aides of the House Intelligence Committee to question witnesses directly during public hearings, according to an official working on the inquiry who described the measure on condition of anonymity because it had yet to be made public.

Lawmakers and aides for several committees were still drafting the resolution Monday afternoon and declined to share many further details. Rep. Jim McGovern, D-Mass., chairman of the House Rules Committee, said he would introduce the resolution today. His panel plans to consider it Wednesday, followed by a vote of the full House on Thursday.

Republicans signaled they would oppose the measure en masse. Shortly after the vote was announced, Rep. Kevin McCarthy of California, the top House Republican, said Democrats called the announcement “an admission that this process has been botched from the start” and said Republicans “will not legitimize” it.

In another shift in strategy, House Democrats will forgo using the federal courts to try to compel testimony from recalcitrant witnesses in their impeachment inquiry and warned lawmakers would instead use the lack of cooperation to bolster their case that Trump has abused his office and obstructed Congress’ investigation.

Rep. Adam Schiff, D-Calif., chairman of the House Intelligence Committee, confirmed the plan after Charles M. Kupperman, the former deputy national security adviser, defied a House subpoena for testimony that had been scheduled for Monday morning.