Republican candidate Ben Carson has zero chance of ever seeing the inside of the Oval Office, according to a former senior advisor to President Barack Obama.

“No Democrat anywhere has spent any time worrying about Ben Carson becoming president of the United States,” Dan Pfeiffer wrote in a CNN op-ed published Tuesday. “I won’t waste your time or mine on him.”

Pfeiffer, who once served as Obama’s communications director, offered this grim assessment of Carson’s political future in a detailed run-down of how “Obama Democrats” see the GOP field. While he spent a considerable amount of time weighing the other candidates’ strengths and weaknesses, those two sentences were his entire take on Carson.

The retired pediatric neurosurgeon is holding steady in recent national polls, pulling ahead of billionaire mogul Donald Trump in a McClatchy-Marist survey released Tuesday. Yet his rise has been threatened by recent investigations into his biography, close ties to a medical supplement company, and academic record, details about which have been proven to be false.

Carson is set to face off against the other Republican candidates during Tuesday night’s Fox Business debate in Milwaukee, Wisconsin.