One? That would do nothing other that send nukes flying by the North. Any US attack would have be fast, totally overwhelming and N. Korea-wide. We have to deal with this sometime. The longer we wait, the greater the destruction of innocents.
The magnitude of what's going on is enormous. Our planners have to ready to protect South Korea, be ready for nukes coming out of N. Korea, be ready for a Chinese confrontation, be ready for a Russian confrontation, be ready to protect Japan, be ready to protect parts of Europe, be ready to protect the United States homeland.
We haven't dealt with a threat like this since WW2.