President Trump will host six senators for a bipartisan dinner at the White House Tuesday, three of whom are among the most vulnerable Democrats up for reelection in 2018.

Those members are Sen. Joe Donelly, Ind., Heidi Heitkamp, N.D., and Joe Manchin, W.Va. Each hail from red states where the Trump’s margin of victory ranges from 19 to 42 percentage points.