speak softly and carry a big stick

speak softly and carry a big stick

Attempt peaceful negotiations while also being prepared for confrontation by displaying one's power, especially elements of force. The phrase was popularized by US President Theodore Roosevelt in a 1903 speech. Because that group is violent and unpredictable, I think you need to speak softly and carry a big stick when you deal with them.
See also: and, big, carry, softly, speak, stick