The belief that the united states had a right to extend its territory across the country was known as: regionalism sectionalism manifest destiny monroe doctrine

Manifest Destiny is the answer your looking for.

i hope this helps my friend

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories

what are two things that greatly the american economy after the war? the huge buildup of u.s. military the beginning of the korean conflict the creation of the gi bill the marshall plan for nations