The westward expansion carried slavery down into the Southwest, into Mississippi, Alabama, crossing the Mississippi River into Louisiana. Finally, by the 1840's, it was pouring into Texas. So the expansion of slavery, which became the major political question of the 1850's, was not just a political issue.
He argued that the essential natural (human) right was “to use his own power, as he will himself for the preservation of his own Nature that is to say of his own Life"
The U.S had no desire to take control of Guam but the tensions were high between the U.S and Spain.. But what really started the was was the sinking of the USS Maine.