The US is already involved. Its just that some people are finding it a bit of a shock to discover how cruel the foreign policy of the US is... its taking time to sink in.
US rushes precision-guided bombs to Israel
It seems to me that the US is trying to drag Syria away from Iran, thus making any future attack on either of the two countries easier. In a sense the talks have already begun, with the intial positions being that the US will not call for a ceasefire and Syria is willing to talk but with no conditions being dicated. As for the people of Lebanon, the US frankly doesn't give a shit. And while all this is going on people seem to be forgetting that Israel is still attacking Gaza.
Israel has destroyed Lebanon's infrastructure, without really harming Hizbullah. That's why ground operations are now being conducted. The result of the air strikes is over 330 people dead in Lebanon, many more injured and over half a million displaced from their homes. Not counting the loss of income, Lebanon seems to have suffered billions of dollars of damage.
I don't think Lebanon will be the same again, with its disintegration into a land of warring tribes looking more likely than recovery. It has enough ethnic/religious/tribal diversity to allow this to happen.