President Donald Trump is wasting no time in his campaign to win over moderate senators to vote for his ultimate Supreme Court pick.

On Thursday night, he rounded up the lawmakers most likely to swing in a private meeting, per Press Secretary Sarah Huckabee Sanders.

Tonight @POTUS met w/ Senators Grassley, Collins, Murkowski, Manchin, Donnelly, and Heitkamp to discuss the Supreme Court vacancy. @POTUS team also talked w/ more than a dozen other Senators today as part of ongoing outreach to get views and advice from both sides of the aisle. — Sarah Sanders (@PressSec) June 29, 2018

Sens. Joe Manchin (D-WV), Joe Donnelly (D-IN), and Heidi Heitkamp (D-ND) are all defending seats in states that Trump won in 2016, forcing them into a careful tightrope walk to appease Independents and moderate Republicans without alienating their liberal base. All three of them voted to confirm Justice Neil Gorsuch.

Per CBS News, Donnelly said that they had a “good conversation” with Trump, while Manchin called the meeting “productive.”

Sens. Susan Collins (R-ME) and Lisa Murkowski (R-AK) are already feeling pressure from both sides about their vote, and Sen. Chuck Grassley (R-IA) has said that he’s counting on Trump choosing someone with “credentials” and “intellect.”