Top contenders to replace Mitch McConnell (R-Ky.) as Senate GOP leader are working the phones with their colleagues — and lining up fundraisers and endorsements for potential new ones, Axios has learned.

Why it matters: Leadership elections thrive on an economy of favors, endorsements and money. The three Johns will have to navigate a fractured GOP and high-stakes election, while avoiding the kind of leadership chaos seen in the House.

• "When and where they endorse — and where they campaign — is an insightful distinction," Zack Roday, a Hill veteran and partner at Ascent, told Axios, saying it can signal which blocs will support each John's leadership.
• Looming over the early jockeying is Sen. Steve Daines (R-Mont.), who privately is being urged by former President Trump to enter the leadership race and is leading Senate Republicans' effort to take back the chamber.

Driving the news: Sen. John Thune (R-S.D.), the second-ranking Senate Republican, is planning to co-host a fundraising event this month with Republican Dave McCormick who is running for U.S. Senate in Pennsylvania, a source familiar with the plans told Axios.

• He will also host a pricey virtual fundraiser with former Maryland Gov. Larry Hogan, with tickets $3,300 a pop, according to an invite for the event obtained by Axios.

Sen. John Cornyn (R-Texas) has an advantage as a top Senate GOP fundraiser for years, raising $13 million this cycle for incumbents, the NRSC and nominees, according to a source familiar with his political operation.

• One senator emphasized how Cornyn spent two years raising significant funds directly for GOP election bids, adding that Thune "missed a trick."
• Thune has also been a powerful fundraiser, raising around $8 million for the NRSC this cycle — more than anyone other than Daines, according to a source familiar.
• Sen. John Barrasso (R-Wyo.) also has been busy fundraising with Ohio candidate Bernie Moreno, Tim Sheehy, who is running in Montana, Sam Brown in Nevada and Jim Banks in Indiana, according to a Barrasso aide.

Endorsements can be tools for building allies too.

• Barrasso has been laying the groundwork for months, being one of the earliest to throw support behind GOP challengers, including for more conservative candidates like Arizona candidate Kari Lake and Moreno.
• He was first to endorse Lake and campaigned with her on Thursday.
• Cornyn endorsed Lake the day after he announced his leadership bid.

The intrigue: Barrasso is the only candidate who has weighed in on the Ohio primary race by backing Trump-endorsed Moreno.

• It's one of few tough Senate primaries for Republicans.
• Some Democratic candidates will try to use the Johns' campaigning efforts to their advantage. Angela Alsobrooks, a Democrat running for the Maryland seat, accused Hogan of "aligning with Republicans who support a national abortion ban," in a statement to Axios.

What to watch: A clear election victory — and Trump's blessing — could put National Republican Senate Committee chair Daines in a prime position come November.

• "I think there is an appetite for people beyond the three Johns," one senator told Axios.

Editor's note: This article was corrected to note that Cornyn endorsed Lake the day after he announced his leadership bid, instead of on the same day.