US has weapons that can be launched from US naval bases in San Francisco or LA and can hit their targets in North Korea. So much for that 7.5 million soldiers...
If North Korea starts something, the very first thing they're going to do is start invading South Korea. Kind of hard to indiscriminately bomb 7.5 million troops when they're interspersed with civilians from an allied nation.
Again, if war was as simple as you guys are making it out to be, Iraq (with its similarly dilapidated armed forces) wouldn't have cost trillions of dollars and thousands of American lives. Now take that, multiply it by a factor of 15 and you've got an idea of the amount of effort it would take to pacify North Korea at a minimum (and this is not including the dynamics of China/Japan/South Korea; unlike Iraq, this would very likely not be a contained conflict where all the fighting takes place in one country).
Also, the only weapons I'm aware of that have trans-oceanic range are nuclear missiles; I could be wrong, but I'm fairly certain conventional weaponry is not made with that kind of range in mind (hence why most cruise missiles are launched from navy ships rather than land bases). Also also, a missile campaign on the scale you're talking about would be obscenely expensive. Missiles do not come cheap.
see, the thing is, if you destroy their entire country, including their leaders, they have absolutely nothing to fight for.
Iraq was different because we couldn't do that. ---