Social patriotism is an openly patriotic standpoint which combines patriotism with socialism. It was first identified at the outset of the First World War when a majority of Social Democrats opted to support the war efforts of their respective governments and abandoned socialist internationalism and worker solidarity.
Social chauvinism can be described as aggressive or fanatical patriotism, particularly during time of war, in support of one's own nation (e.g., government, culture, etc.) versus other nation(s), displayed by those who are socialists or social democrats. During World War I, most left-wing political parties took a social-chauvinist stand, with few exceptions. Most Socialists gave up their anti-militarism and their belief in international unity among the working class in favour of "defense of the fatherland", and turned to social-chauvinism, most notably the German Social Democratic Party and the French Section of the Workers' International.
A break with social patriotism was called, leading to the foundation of a Third International.