blank cheque BrE
blank check AmE

That is not the same as a military blank check.

"I think the elected public officials should be in control, rather than give the police a blank check."

I, for one, am not willing to give the federal government a blank check.

"But why do I get the feeling you're asking me to sign a blank check?"

And remember, if things get tough, you have a blank check.

"Well, the people of Georgia said no to that blank check."

Corporate air travel is no longer the land of the blank check.

But did he really want to issue such a blank check to Whoever?

"He didn't want to give them a blank check for a month."

A blank check from a financial firm on the 101st floor.