Steve Bannon was unhappy with President Trump's decision to pick Mike Pence as his running mate and said Pence's selection is the "price we pay" for Republicans who opposed Trump's candidacy.

Bannon, chairman of Breitbart News and former White House chief strategist, expressed his displeasure with the decision to tap the former Indiana governor as Trump's vice presidential running mate in an email exchange obtained by BuzzFeed. The emails were sent one month before Bannon took over as chief executive of Trump's presidential campaign, and the day Trump announced Pence as his running mate.

Bannon was serving as executive chairman of Breitbart News at the time, a position he would return to after leaving his post as White House chief strategist in August.

In one email sent July 15, 2016, Milo Yiannopoulos, who then served as Breitbart's technology editor, told Bannon and Breitbart editor Alex Marlow that Pence "seems like a bad pick."

"Should I tweet something ambivalent about him? People are telling me Trump likely didn't want this. …What's our party line on this?" Yiannopoulos asked in the email, according to BuzzFeed.

In response, Bannon said Pence's selection as Trump's running mate was the "price we pay" for the movement of Republicans opposed to Trump.

"This is the price we pay for cruzbots and #nevertrump movement. An unfortunate necessity…very. feel free to do whatever u want. we, as always, will remain above it all," he wrote.

Bannon later approved a column from Yiannopoulos published July 18, 2016, that invited Pence to "our big gay party for Trump," BuzzFeed reported.

In the wake of his departure from the White House, Bannon has started working to recruit conservative candidates to challenge incumbent GOP members of Congress.

Bannon backed Roy Moore, who defeated Sen. Luther Strange, R-Ala., in the special election primary for the seat vacated by Attorney General Jeff Sessions. He has also reportedly been in discussions with GOP megadonor Foster Friess and Blackwater founder Erik Prince about challenging Sen. John Barrasso, R-Wyo.