The Missouri Republican is preparing to file subpoena requests for witnesses and documents that Democrats and Republicans alike won’t want to vote on. Hawley’s strategy harmonizes with plans from GOP Sens. Ted Cruz of Texas and Rand Paul of Kentucky to force votes to hear from Hunter Biden, the former vice president’s son who was on the board of Ukrainian energy company Burisma.

Their tactics are intended to convince a handful of senators to sink a vote next week to consider new evidence in President Donald Trump’s impeachment trial. Trump’s attempt to pressure Ukraine to investigate the Bidens is at the heart of the impeachment case against the president.

If the witness vote succeeds, Hawley aims to force votes on subpoenas for House Intelligence Chairman Schiff (D-Calif.), Vice President Biden, Hunter Biden, Intelligence Community Inspector General Michael Atkinson, the still-unnamed whistleblower who reported Trump’s July call with the Ukrainian president and a reported acquaintance of the whistleblower’s.