Sen. Mike Rounds (R-S.D.) on Monday teased “a logic that a lot of people aren’t talking about yet” which may help sway public opinion over President Donald Trump’s controversial plan to accept a luxury $400 million jumbo jet — to be temporarily used as Air Force One — from Qatar’s ruling family.

But Rounds kept silent on what the actual logic is, telling CNN’s Kaitlan Collins that “a lot of it’s still classified” and then admitting: “I probably shouldn’t be breaking that story.”

Collins had earlier asked Rounds if he was “ethically and optically” comfortable “with the president flying on a plane that was gifted to him by Qatar?”

Trump has drawn criticism from across the the political divide for his willingness to accept a Boeing 747 from Qatar, to be used as Air Force One while two new presidential planes are being built. The Qatari jet will then be transferred to Trump’s presidential library when he leaves office.

Rounds replied to Collins: