Henry David Thoreau as he writes in his essay "Civil Disobedience"
There was substantial support for the War of 1812, and the population was equally divided on the Mexican American War.
Many by enlisting and serving.
Mexico never had states. And I am sure there were some Mexicans supporting U.S.A during the war.
At the start, no one. When the US finally ended its Civil War, president Lincoln offered arms and financial support to the Mexican president Benito Juarez.
He wanted the Independence of Texas validated.
John Quincy Adams was in opposition to the Mexican War. John Quincy Adams served as the 6th President of the United States.
Texas supplied men for the US Army as did other states.
Yes, in that they supported Manifest Destiny.
Abraham Lincoln spoke out against it when he was a Whig Congressman.
He served in an artillery unit. It was described as a flying artillery, which meant it was used for close support of the infantry.A good source on the Mexican War and the Civil War generals who fought in that earlier war is John Eisenhower's "So Far From God".
Yes, this promise was relayed through the Zimmerman Telegram.
Mexican War