Manifest Destiny, 2
Historians tend to refer to the time span between the War of 1812 with Britain and the start of the American Civil War in 1860 as being the actual age of Manifest Destiny, although it can be argued that the sentiment at the core of Manifest Destiny continues to have proponents of one sort or another. Nowadays, the connotation of Manifest Destiny tends to be one of unjustified imperialistic actions, such as the current pre-emptive invasion of Iraq by the United States.
Despite negative associations, it is important to consider historical periods in their appropriate context. Manifest Destiny was considered by many to be nothing less than the God-given right of the United States to control lands and territories which make up part of the contiguous 48 states even today.