"We expect he's going to continue to be a strong voice for immigration reform there, have great or even greater influence there than he had in the Senate," he said.
DeMint was also instrumental in helping elect so-called Tea Party members to the Senate in 2010 who would ostensibly reject compromises on conservative principles.
But coming off an election in which Latino voters largely abandoned the Republican Party, some of the senators DeMint endorsed have spoken about the need to pass some sort of immigration reform, including Rand Paul (R-Ky.) and Marco Rubio (R-Fla.)
DeMint's resignation is no guarantee that his successor will have different views on immigration, but advocates said that he's unlikely to wield the same influence as DeMint. The timing of the senator's departure carries significant consequences heading into next year.