He was elected governor of Massachusetts in 1919 and in 1920 was reelected under circumstances that attracted nation-wide attention.
In 1907 he took a prominent part in advocating the ending, rather than the mending, of the House of Lords; and in 1908 he was elected chairman of the party, a post which he held for two years and to which he was reelected in the autumn of 1914 when the then chairman, Mr. Ramsay Macdonald, had to resign owing to his pacifist views.
He was elected to the Canadian House of Commons in the general election of 1908, and was reelected in 1911 and 1917.
He was an ardent Liberal in politics, and in 1880 he was elected to parliament for the Tower Hamlets division of London; in 1885 he was returned for South Aberdeen, where he was reelected on succeeding occasions.
He was elected governor of Iowa in 1902 and reelected for two succeeding terms. He filled the unexpired term of Senator Allison in 1908, and was reelected to the U.S. Senate in 1909 and 1915.