Samuel was the last member of the Liberal Party proper to hold one of the four Great Offices of State (as Home Secretary from 1931 to 1932 in the National Government of Ramsay MacDonald).

Samuel worked through the influence of Charles Darwin and the book On Compromise by senior Liberal politician John Morley.

[10] He was appointed to the Cabinet in 1909 by Prime Minister H. H. Asquith, first as Chancellor of the Duchy of Lancaster and then as Postmaster General, President of the Local Government Board and eventually Home Secretary.

As Home Secretary, Samuel faced a shortage of manpower needed to fight in World War I, and he initiated legislation to offer thousands of Russian refugees (many of them young Jews) a choice between conscription into the British Army or returning to Russia for military service.

Samuel did not want to enter into a detailed discussion of his plans but mentioned that "the Jews would have to build railways, harbours, a university, a network of schools, etc", as well as potentially a Temple in "modernised form".

[14] The memorandum stated, "I am assured that the solution of the problem of Palestine which would be much the most welcome to the leaders and supporters of the Zionist movement throughout the world would be the annexation of the country to the British Empire".

Nonetheless, the military government withdrew to Cairo in preparation for the expected British Mandate, which was finally granted two years later by the League of Nations.

[18] Technically, Allenby noted, the appointment was illegal, as a civil administration that would compel the inhabitants of an occupied country to express their allegiance to it before a formal peace treaty (with the Ottoman Empire) was signed violated both military law and the Hague Convention.

Lord Curzon said that no "disparaging" remarks had been made during the debate but that "very grave doubts have been expressed as to the wisdom of sending a Jewish Administrator to the country at this moment".

Questions in the House of Commons of the period also show much concern about the choice of Samuel: "what action has been taken to placate the Arab population... and thereby put an end to racial tension".

Three months after his arrival, The Morning Post commented: "Sir Herbert Samuel's appointment as High Commissioner was regarded by everyone, except Jews, as a serious mistake."

He hoped to gain Arab participation in mandate affairs and to guard their civil and economic rights, but refused them any authority that could be used to stop Jewish immigration and land purchase.

At the same time, he enjoyed the respect of the Jewish community, and he was honoured by being called to the Torah at the Hurva synagogue in the Old City of Jerusalem.

According to Wasserstein: He is remembered kindly neither by the majority of Zionist historians, who tend to regard him as one of the originators of the process whereby the Balfour Declaration in favour of Zionism was gradually diluted and ultimately betrayed by Great Britain, nor by Arab nationalists who regard him as a personification of the alliance between Zionism and British imperialism and as one of those responsible for the displacement of the Palestinian Arabs from their homeland.

[29]On his return to Britain in 1925, Prime Minister Stanley Baldwin asked Samuel to look into the problems of the mining industry.

However the government's willingness to consider the introduction of protectionist tariffs and call a general election to seek a mandate led to the Liberal Party fragmenting into three distinct groups.

Finally, in November 1933, Samuel and the bulk of the Liberal MPs crossed the floor of the House of Commons and opposed the government outright.

In 1937, he was granted the title Viscount Samuel; later that year, Samuel, despite his Jewish ancestry, aligned himself with Prime Minister Neville Chamberlain's appeasement policy towards Adolf Hitler, urged that Germany be cleared of its 1914 war guilt and recommended the return of German colonies lost after the war.

During the 1951 general election, on 15 October 1951, Samuel became the first British politician to deliver a party political broadcast on television.

[32] On 17 November 1897 Samuel married his first cousin Beatrice Miriam (1871–1959), daughter of Ellis Abraham Franklin, a banker.