Two of the "Three Johns" tapped as potential heirs to outgoing Senate GOP Leader Mitch McConnell have faced allegations of disloyalty personally leveled by former President Trump.

Why it matters: McConnell's exit in November is a death knell for the old guard GOP establishment. MAGA is eager to fill the void.

• Sens. John Thune (R-S.D.) and John Cornyn (R-Texas) — McConnell deputies whom Trump has shamed as "RINOs" — face an uphill climb in their quest to become the next GOP leader.
• Sen. John Barrasso (R-Wyo.), who savvily endorsed Trump in January, enters the race as the MAGA-friendly of the "Three Johns."

Between the lines: A sizable bloc of Republican senators still wants their leadership to function as a bulwark against Trumpian excesses, especially given the far-right chaos that has plagued the House GOP majority.

• Thune, the No. 2 Senate Republican, agonized over running for re-election in 2022 after Trump attacked him for his refusal to support overturning the results of the 2020 election.
• Cornyn, Thune's predecessor as GOP whip, faced backlash among conservatives in 2022 for his handling of bipartisan gun reform negotiations after the Uvalde, Texas, school shooting.

The two senators will likely start out as favorites in November's race to replace McConnell, but the vocal bloc of pro-Trump senators who have taken office since 2017 will complicate their path to a majority.

• Look to the 10 who voted for Sen. Rick Scott (R-Fla.) in November 2022's leadership election — the first contested vote that McConnell ever faced — to act as a decisively pro-Trump bloc.

The intrigue: Thune signaled his willingness to kiss the ring when he finally endorsed Trump on Sunday, but Cornyn — though he's also endorsed Trump — appears ready to brawl with his MAGA detractors.

• "It will be difficult for Cornyn to be an effective leader since he is anti-Trump, anti-gun, and will be focused on his highly competitive primary campaign in 2026," tweeted Texas Attorney General Ken Paxton on Wednesday.
• "Hard to run from prison, Ken," Cornyn shot back at the indicted Trump surrogate.