Vice President Mike Pence is recording a robocall for the Republican running nominee in Tuesday’s special House election in Kansas, a clear sign of concern that the Democrats could flip this solid GOP seat.

Sources told the Washington Examiner on Friday that Pence would record a call urging Republicans in Kansas’ Wichita-area 4th district to get out and vote for state Treasurer Ron Estes, who is locked in a tight battle with Democrat James Thompson.

The White House political office, led by political director Bill Stepien, has joined what has become a party-wide effort to save a seat that President Trump won by nearly 30 points in November. The White House did not immediately respond to a request for comment.

“Ron’s run a horrible campaign. Hasn’t raised much money, his ads are abysmal — no energy,” a Kansas Republican operative said, on condition of anonymity in order to speak candidly. “It’s a low turnout special and weird things happen.”