gunboat diplomacy

noun

the practice of backing up diplomatic efforts with a visible show of military might

The pursuit of foreign policy objectives with the aid of conspicuous displays of military power.
“The British and French, who had sought to make policy by reviving 19th century gunboat diplomacy, had temporarily lost their credentials for world statesmanship.”
“China has ratcheted up its standard gunboat diplomacy—the repeated warnings that it would use force if necessary to unite the island and mainland—more than a month before Taiwanese voters go to the polls.”