Attacking the press for liberal bias is a staple of Republican campaigns -- and it all began in 1964

Decades before President Donald Trump ever attacked the media, Senator Barry Goldwater introduced a new idea to the presidential campaign trail: liberal media bias.

Goldwater was 1964's Republican presidential candidate, and he was convinced that the journalists covering the campaign were infusing their reporting with a left-leaning tilt while claiming to be neutral observers. As a staunch conservative, Goldwater believed this bias put him at a distinct disadvantage in his race against President Lyndon Johnson.

Struggling in the polls, he insisted that his message — rolling back the New Deal...