Sen. Harry ReidHarry ReidVirginia was a wave election, but without real change, the tide will turn again Top Lobbyists 2017: Grass roots Boehner confronted Reid after criticism from Senate floor MORE (D-Nev.) won't be stumping for the opponent of his Republican counterpart in the Kentucky Senate race, he said Friday.

During an interview with Bloomberg's Al Hunt set to air Friday night, Reid said he wouldn't campaign with Kentucky Secretary of State Alison Lundergan Grimes, the likely Democratic nominee, against Sen. Mitch McConnellAddison (Mitch) Mitchell McConnellAlabama election has GOP racing against the clock McConnell PAC demands Moore return its money Klobuchar taking over Franken's sexual assault bill MORE (R-Ky.)

"Oh, no. No, I — that — I'm a traditionalist here, and that isn't anything I've ever done and will not do," Reid said.

Reid said last year he wouldn't campaign against the minority leader because he didn't think it was "appropriate," reflecting a longstanding tradition in the Senate for party leaders to stay out of their counterparts' races.

The Kentucky Senate race is Democrats' top offensive target this cycle. The party believes McConnell's low popularity in his home state gives them a rare pickup opportunity in a map that has them largely on defense.

Lundergan Grimes, however, could well fare better in her race without Reid's involvement.

Republicans have made Reid the centerpiece of their coal-focused attacks on Lundergan Grimes, noting he once said that "coal makes us sick" and suggesting she agrees with that position — a losing one in Kentucky, where coal makes up a large portion of the economy.

Reid did host a fundraiser for Lundergan Grimes in October, which drew Republican attacks.

Asked by Hunt whether he'll be raising money for her going forward, he was noncommittal. 

"I don't think she needs much of my help. She seems to be doing pretty well," he said.