You make one fatal assumption, however. You believe that the North Koreans would believe that we would actually attack them. There's no way we would, right now. Maybe 10 years ago they would have believed us capable, when we weren't involved in Iraq and Afghanistan, but there's no way now.
I am not against diplomacy backed up by force (you do need carrots to go along with those sticks, though). The worry by you conservatives would be, of course, you have to be willing to actually use that force when push comes to shove. I might have said some contradictory things before, but I do believe that force is sometimes necessary. You just have to know when to limit it. I believe that the invasion of Grenada, the invasion of Panama, the first Gulf War, and Clinton's Operation Desert Fox were all necessary and carried out well. We did not occupy for five years and we only took down the government when we knew what we were getting into - we knew our limits.
I hate to sound like that liberal that always goes back to blaming Bush, but: Bush did not know his limits. He unnecessarily invaded Iraq, which took away press, money, supplies, troops, and most importantly public attention away from Afghanistan. Maybe we could have launched airstrikes in Iraq. Maybe that would have been acceptable; however, overthrowing the Hussein regime took it to far. And Bush, Cheney, Rumsfeld and Co. didn't even do it well! The occupation of Iraq was a failure.
Anyway, I'm getting a little side tracked. My point is this: negotiations carried out with the threat of force are always great, as long as you know your limits.
So: how about in 10 years, when we're out of Iraq and Afghanistan (I can't wait), we settle down and talk to those Russians. Tell them, hey, you invade Germany from your newly established bases in conquered Poland - we'll kick your ass.