Charm offensive

Meaning

A publicity campaign, usually by politicians, that attempts to attract supporters by emphasizing their charisma or trustworthiness.

Origin

This dates from the mid-20th century and the first recording of it we have is in the California newspaper The Fresno Bee Republican, October 1956:

War is no longer just around the corner. [General Alfred M.] Gruenther warned, though, that after the "launching of the Russian charm offensive, there is a danger of the democracies relaxing their vigilance."