Charm offensive

The expression ‘charm offensive’ dates from the mid-20th century and was initially used to describe the political tactics of adversaries in the Cold War.

The first use of it in print that I know of is from the New York newspaper The Elmira Advertiser, July 1955:

What seems to be indicated here is that the Soviet reply was based not upon the merits of the case but on the propaganda value of an apparent conciliatory position in view of the fact that the current Red “charm offensive” may have been rudely jolted by some trigger-happy Communist airmen.

The inclusion of the quotation marks around the phrase indicates that the paper’s readers wouldn’t have been expected to be familiar with it.

The expression has since been adopted more widely and is applied to any situation where someone attempts to use a charming manner to their own advantage.