Supreme Court nominee Brett Kavanaugh will ramp up his behind-the-scenes preparation over the next three weeks for his confirmation hearing before the Senate Judiciary Committee, starting with more one-on-one meetings Wednesday with senators whose votes could prove pivotal.

Kavanaugh, who is more used to asking questions from the dais as a judge on the U.S. Court of Appeals for the District of Columbia Circuit for the past 12 years, has been going through mock hearings that last several hours with questions from people assigned to the role of different senators, a White House official said.

Next week, that will include full mock hearings to condition Kavanaugh for several all-day sessions of questioning from committee members, the official said.

While Kavanaugh appears likely to have enough Republican votes to become President Donald Trump’s second appointment to the high court, the multiday confirmation hearing will be a critical and widely watched event as Democrats press him on numerous concerns about his legal views, particularly on access to abortion, health care and presidential power.

Kavanaugh’s preparations are similar to previous Supreme Court nominees. A misstep could complicate confirmation efforts and a good performance could deflate opposition.

Those helping him, including former Arizona Republican Sen. Jon Kyl, employees from the Justice Department and the White House counsel’s office, have gone back and forth with Kavanaugh, gaming out responses to the most contentious issues and hot-button cases, the official said.

Kavanaugh still has meetings with senators whose votes could be crucial for his confirmation, starting Wednesday with Sens. Joe Donnelly of Indiana and Heidi Heitkamp of North Dakota. Both Democrats are up for re-election in states Donald Trump won in the 2016 presidential election.

Sen. Joe Manchin III of West Virginia, also up for re-election in a Trump state, met with Kavanaugh on July 30, the only Democrat among the 47 meetings with senators so far. Manchin, Donnelly and Heitkamp were the only three Democrats to vote for Trump’s first Supreme Court nominee, Neil Gorsuch.

Democratic Sen. Claire McCaskill, who announced she would meet with Kavanaugh on Aug. 21, told reporters earlier this month that the Kavanaugh nomination “is not a ‘political winner.’” The calls and emails coming into her office are evenly split between those who want her to vote for and against the judge.

Minority Leader Charles E. Schumer of New York and Sen. Dianne Feinstein of California, the top Democrat on the Judiciary Committee, also plan to meet with Kavanaugh and press him to back the release of more White House documents from his work in the George W. Bush administration, the Washington Post reported.

Kavanaugh has also yet to meet with Sens. Lisa Murkowski of Alaska and Susan Collins of Maine, two Republicans targeted by Democrats and liberal advocacy groups as potential votes against Kavanaugh because of their prior stances on access to abortion and health care. Murkowski and Collins previously have said they would meet with Kavanaugh during the August session.

Republicans have only 50 votes right now because Sen. John McCain of Arizona is battling brain cancer at home. So if all Democrats oppose Kavanaugh’s nomination, the loss of one Republican vote would sink it.