it takes two to make a bargain—both parties must agree in order for a deal to be successful:
- “We decided you should make dinner tonight, right?” “No, we didn’t decide that; you decided that. It takes two to make a bargain.”
it takes two to tango —(also: it takes two to make a quarrel) both parties should share responsibility:
- All nations that go to war have some guilt. It always takes two to tango, you know.
See also: that makes two of us / two can play at this game.