As noted by Political Wire:

“I’m telling you the single biggest issue, as bad as the border is and it’s horrible, horrible what they’re doing, they’re destroying our country — but as bad as that is, the single biggest issue — the issue that gets the most pull, the most respect, the biggest cheers — is talking about the election fraud of the 2020 presidential election.”

— Donald Trump, quoted by Politico.

Playbook: “That’s a problem for Republicans. Many of them want to make the midterm elections about the issues — inflation, the border, Afghanistan, etc. — to set the election up as a referendum on Biden’s presidency. Trump doesn’t.”