Original sentence: In the mid-20th century, the classical liberals often formed an alliance with social conservatives (an ideology known as liberal conservatism)
Edited sentence: In Europe, the same two sides formed but with different labels: what are called social liberals in America are called simply socialists in Europe, and their party is usually called the Labour Party or Socialist Party.In the mid-20th century, the classical liberals often formed an alliance with social conservatives (an ideology known as liberal conservatism); in the United States, they did this under the banner of the Republican Party