A 19th-century US political doctrine advocating territorial expansion. It was proclaimed by John O’Sullivan as “Our manifest destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions”. A tenet of the Democratic Party, it gained support among Whig, and later Republican, interests, and played a significant part in raising popular support for the annexation of Texas (1845) and the Mexican–American War (1846–48). It was later invoked by Seward in the purchase of Alaska (1867), and re-emerged in the 1890s with the annexation of Hawaii and the acquisition of Spanish territories in the Spanish–American War.