Before "Country First" (one of John McCain's slogans in this year's campaign), there was "America First."
Interestingly, this slogan was used in two different years, by two different political parties, in the early twentieth century, and again in 1992 (in a primary campaign).
In 1916, Democrat Woodrow Wilson's campaign employed it in the U.S. presidential campaign. In that election, the slogan was a reference to the Wilson administration having kept the country out of the war in Europe; and the slogan “Wilson, That’s All!” had been employed previously in advertisements for a brand of whiskey (according to Michael Beschloss in his American Heritage Illustrated History of The Presidents). Wilson's opponent, Republican Charles Evans Hughes, blamed the concerted “He Kept Us Out of War”/“America First” propaganda effort that so heavily used vivid pictorial posters and billboards for his defeat.
In 1920, it was the Republican campaign for Warren G. Harding that used this slogan, exploiting the public's disillusionment with World War I and its aftermath. One can see the "America First" slogan in Howard Chandler Christy’s idealized rendition of Harding with the candidate dramatically making the "V" sign with one hand and holding an American flag with the other.
Patrick Buchanan, who ran for the Republican presidential nomination in 1992, also used the theme "America First." According to Ron Faucheux, "Buchanan's enemies drew unflattering comparisons between his slogan and the same one that had been used a half-century earlier by the 'America First' committee, an isolationist group that opposed U.S. entry into World War II." The "America First" committee's goal had been to prevent the U.S. from entering World War II.
McCain's "Country First" slogan does not imply any isolationism. In the present campaign, McCain is trying to say that the Republican candidate puts the "country" before any political considerations. For example, McCain called for the "surge" in Iraq when this was an unpopular strategy, even among members of his own party.