Korea again?

The North Koreans have fired artillery at the South Korean people again.
What is/should be the stance of the USA? Will Obama get tough and demand retaliation or shall he follow the last administration into further meetings and appeasement?
What recourse do we have with the Chinese, who seem to be the only ally and supporter of the North Korean leaders?
My take---blow the North to hell and completely destroy their nuclear facilities and military OR bring home our 28000 troops that are in South Korea and let the locals beat each others brains out.
This posturing and expense of maintaining a small army there and then not using it except for a show is foolish adventure, better suited to the 19th century gunboat diplomacy.
And finally-does any man alive think Obama has the whatever it takes to really fight a war against the North Koreans????