Spencer Cavendish, 8th Duke of Devonshire

Spencer Compton Cavendish, 8th Duke of Devonshire (23 July 1833 – 24 March 1908), styled Lord Cavendish of Keighley between 1834 and 1858 and Marquess of Hartington between 1858 and 1891, was a British statesman. He has the distinction of having held leading positions in three political parties: at different times he led Liberal Party, the Liberal Unionist Party and the Conservative Party in either the House of Commons or the House of Lords. After 1886 he increasingly voted with the Conservatives. He declined to become prime minister on three occasions, because the circumstances were never right. Historian and politician Roy Jenkins said he was "too easy-going and too little of a party man". He held some passions, but he rarely displayed them regarding the most controversial issues of the day.

Devonshire was the eldest son of William Cavendish, 2nd Earl of Burlington, who succeeded his cousin as Duke of Devonshire in 1858, and Lady Blanche Cavendish (née Howard). Lord Frederick Cavendish and Lord Edward Cavendish were his younger brothers. He was educated at Trinity College, Cambridge, where he graduated as MA in 1854, having taken a Second in the Mathematical Tripos. He later was made honorary LLD in 1862, and as DCL at Oxford University in 1878.

In later life he continued his interests in education as Chancellor of his old university from 1892, and of Manchester University from 1907 until his death. He was Lord Rector of Edinburgh University from 1877 to 1880.

After joining the special mission to Russia for Alexander II's accession, Lord Cavendish of Keighley (as he was styled at the time) entered Parliament in the 1857 general election, when he was returned for North Lancashire as a Liberal (his title "Lord Hartington", by which he became known in 1858, was a courtesy title; not being a peer in his own right, he was eligible to sit in the Commons until 1891, when he succeeded his father as Duke of Devonshire). Between 1863 and 1874, Lord Hartington held various Government posts, including Civil Lord of the Admiralty and Under-Secretary of State for War under Palmerston and Earl Russell. In the 1868 general election he lost his seat; having refused the Lord Lieutenancy of Ireland, he was made Postmaster-General, without a seat in the Cabinet. The next year he re-entered the Commons, having been returned for Radnor. In 1870 Hartington reluctantly accepted the post of Chief Secretary for Ireland in Gladstone's first government.

In 1875 – the year following Liberal defeat at a general election — he succeeded William Ewart Gladstone as Leader of the Liberal opposition in the House of Commons, after the other serious contender, W. E. Forster, had indicated that he was not interested in the post. The following year, however, Gladstone returned to active political life in the campaign against Turkey's Bulgarian Atrocities. The relative political fortunes of Gladstone and Hartington fluctuated – Gladstone was not popular at the time of Benjamin Disraeli's triumph at the Congress of Berlin, but the Midlothian Campaigns of 1879–80 marked him out as the Liberals' foremost public campaigner.

In 1880, after Disraeli's government lost the general election, Hartington was invited by the Queen to form a government, but declined – as did the Earl Granville, Liberal Leader in the House of Lords – after Gladstone made it clear that he would not serve under anybody else. Hartington chose instead to serve in Gladstone's second government as Secretary of State for India (1880–1882) and Secretary of State for War (1882–1885).

In 1884 he was instrumental in persuading Gladstone to send General Gordon on a mission to evacuate the Sudan. Despite the repeated objections of consul-general in Egypt Sir Evelyn Baring, the indomitable Gordon was finally sent to Khartoum, where he did exactly the opposite of what he was sent to do, resulting in the siege of the city by the Mahdi and the final massacre of Gordon and 20,000 Arabs. Before the imminent catastrophe, Hartington persuaded Gladstone to send troops for the relief of Khartoum which arrived two days too late. A considerable number of the Conservative party long held him chiefly responsible for the "betrayal of Gordon". His lethargic manner, apart from his position as war minister, helped to associate him in their minds with a disaster which emphasized the fact that the government acted "too late"; but Gladstone and Lord Granville were no less responsible than he.

Hartington became increasingly uneasy with Gladstone's Irish policies, especially after the murder of his younger brother Lord Frederick Cavendish in Phoenix Park. After being elected in December 1885 for the newly created Rossendale Division of Lancashire, he broke with Gladstone altogether. He declined to serve in Gladstone's third government, formed after Gladstone came out in favour of Irish Home Rule (unlike Joseph Chamberlain, who accepted the Local Government Board but then resigned), and after opposing the First Home Rule Bill became the leader of the Liberal Unionists. After the general election of 1886 Hartington declined to become Prime Minister, preferring instead to hold the balance of power in the House of Commons and give support from the back benches to the second Conservative government of Lord Salisbury. Early in 1887, after the resignation of Lord Randolph Churchill, Salisbury offered to step down and serve in a government under Hartington, who now declined the premiership for the third time. Instead, the Liberal Unionist George Goschen accepted the Exchequer in Churchill's place.