As the civil war began president lincoln accepted the belief that

it was time to end slavery throughout the United States.

Explanation:

In 1863, Lincoln's Emancipation Proclamation, which announced that all people held as slaves were free, affected the Union's Civil War efforts by  increasing the number of troops who could join the Union. The reason is the new law permitted African Americans to enlist in the military.

in 1803 the louisiana purchase took place, doubling the size of the country. by 1840 almost 7 million americans had migrated westward in hopes of securing land and being prosperous. the belief that settlers were destined to expand to the west is often referred to as manifest destiny.

explanation: