Tom Tugendhat
James Cleverly came top of the latest ballot following a strong performance at last week's Conservative conference.
The move has been hailed by Joe Biden - but criticised by Tory leadership contenders.
She appears to have taken a leaf out of Liz Truss's book.
He said his leadership revival should take the clip down.
Tom Tugendhat said he had shown "a fundamental misunderstanding of military operations".
The four remaining candidates vying to succeed Rishi Sunak will face off next week at a party conference like no other.
Fewer than 10% of the public think any of them would make the party favourites to win the next election.
The X boss's comments were "delusional", the shadow security minister said.
A majority did agree a backing from Liz Truss would give that candidate a worst chance of winning, though.
The winner will be the sixth Conservative Party leader since 2016.