Complex sentence: As the war progressed, Haldane moved more and more to the left, and when Ramsay MacDonald and the Labour Party came to power in 1924 with very little support in the House of Lords, Haldane was recruited to serve once again as Lord Chancellor.
Split into simpler sentences: As the war progressed, Haldane moved more and more to the left. When the Labour government was formed by Ramsay MacDonald, Haldane was recruited to serve once again as Lord Chancellor.