You can declare war and not invade. It sounds like you are equating war with a full-scale invasion. We can declare war and fight strategically with well-targeted missiles, bombs, etc.
I wouldn't be opposed to an invasion, though, so long as the culprit is found to be a country, or a group supported or harbored by a country.
Your estimate of Vietnam * 1 million is total overkill bro. Maybe if this became WW3, but not war with a small country with no nuclear capability.