to capture rebel leaders and take away stores of ammunition
A nation or empire can do it without bloodshed if both countries agree to it. It is called Annexation.
To encourage settlement in the West by giving government-owned land to small farmers Congress passed three acts in 1862 to turn public lands into private property. allowed any head of household over the age of 21 to claim 160 acres of land. Each person had to build a home on the land, make improvements, and farm the land for five years before being granted full ownership of the land by the government. Nearly 2 million people applied for land claims under this.
To protect spain and the people of spain from non-spain forces. Even if he was a monarchist, and ensure himself as protector