Senate leaders remained at an impasse Thursday over the scope of an impeachment trial of President Trump, as his reelection campaign claimed that a backlash from the House proceedings had helped him raise $46 million in the final three months of 2019.

Aides to Senate Majority Leader Mitch McConnell (R-Ky.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) said the two men had not spoken over the holidays about the standoff. House Speaker Nancy Pelosi (D-Calif.) has held off sending articles of impeachment — alleging abuse of power and obstruction of Congress — to the Senate as Democrats seek guarantees about witnesses and documents that will be subpoenaed regarding Trump’s conduct toward Ukraine.

At the heart of the Democrats’ case is the allegation that Trump tried to leverage a White House meeting and military aid, sought by Ukraine to combat Russian military aggression, to pressure Ukrainian President Volodymyr Zelensky to launch an investigation of former vice president Joe Biden and his son Hunter Biden, as well as a probe of an unfounded theory that Kyiv conspired with Democrats to interfere in the 2016 presidential election.