Have a/(one's) finger on the button phrase
Have the power to launch a nuclear attack, especially used to imply that the president of the United States
A: Speaking of the nuclear bomb, do you know who has a finger on the button in the US? B; The president, I guess.
What if the president of the US has a finger on the button?
The verb "have" must be conjugated according to its tense.
The origin of this phrase is not clear.
Used to describe a situation when people say nothing and feel worried, embarrassed or uncomfortable
A heavy silence fell upon the room after Jane refused John's proposal.