Would North Korea Be Willing to Use Their Missiles to Launch Future Provocations Against the United States?

Here is an excerpt from article forwarded to me that speculates how the Kim regime may try and use their missiles to launch provocations against the United States to cause a split in the US-ROK alliance:

You can read the rest at the link.  However, I don’t think the Kim regime would use their missiles to launch a provocation against the United States because the South Koreans would have to back US retaliations as part of the US-ROK alliance.  However, where things muddier is what if he launched a missile provocation against Japan?  Would the South Korean government be willing to back retaliation in support of Japan?