Colorado Senate Democrat candidate Andrew Romanoff has called for former Colorado Gov. John Hickenlooper to drop out of the Senate race in the wake of his ethics controversy.

The Colorado Independent Ethics Commission slapped Hickenlooper last week with the highest ethics penalty for his use of a corporate jet and Maserati limo.

Romanoff charged during a debate last week that Hickenlooper’s ethics scandal will lead to endless attack ads, which could jeopardize his candidacy in favor of incumbent Sen. Cory Garnder (R-CO).

During a debate with Hickenlooper last Tuesday, Romanoff said, “Look, John Hickenlooper just wrote the Republicans’ ad against him twice now. The truth is that John Hickenlooper represents a threat that we cannot afford.”

Romanoff, who supports Medicare for All, beat Hickenlooper in the Colorado Democrat caucuses last March. Sen. Bernie Sanders (I-VT) also won Colorado during the March Democrat presidential primary.

Romanoff has called for Hickenlooper to drop out of the Senate race. The Colorado Senate primary is on June 30.

The National Republican Senatorial Committee (NRSC) has already launched an attack ad against Hickenlooper, detailing his ethics violations, which includes being the first person to be ever held in contempt by the Colorado ethics commission.

Jesse Hunt, the communications director for the NRSC, said that the ethics violations present a “serious problem with him for Colorado voters.”

One Republican pollster said that Hickenlooper’s ethics scandal could give Gardner an advantage during the Senate general election against the former Colorado governor.

“There are folks that — not everything is ideological,” one GOP official told the Hill.

The Republican official added, “They might be voting against Republicans and Trump this time around. But I do think there are nonideological voters out there that will go for Cory Gardner.”

Sean Moran is a congressional reporter for Breitbart News. Follow him on Twitter @SeanMoran3.