Generally speaking, yes it is true that the <span>Opium Wars opened Asian nations, particularly China, to trade with Europe, since through these wars the British practically "forced" China to trade with them. </span>
The Siege of Vicksburg was important to the Union troops because they were able to take control of the Mississippi River. This allowed the Union troops to cut the Confederacy in half and allowed the Union to cut of supplies/resources to Confederate states.
The Battle of Gettysburg was an important Union win because this was the last time in the Civil War that the Confederate troops truly invaded the North. After this battle they did not invade any state north of Pennsylvania.
He failed in his attempt to develop a more moral and less imperialistic policy in Latin American because he disregarded his ambassador by sending him home for being too aggressive. He also made decisions and took actions without the consent of the US Government. He ordered the Mexican port of Veracruz to be seized.
