My preference would be, Cotton kept his mouth shut until the deal was done.. as I recall when asked, President Trump did say the idea had been discussed...not that he initiated the idea.
He was letting trump off the hook by taking the blame.
Nah - the Title makes it sound like he’s afraid Trump is taking credit for the idea...and CVotton is letting everyone know he is on board with it so as to not alienate him from Trump in either of their constituent bases.
The fact that Trump aired it shows he supports what Cotton came up with and was willing to shoulder any flak.
If/when it ever goes through, you can bet Trump will have Cotton beside him when the announcement happens.