The US military want to see Lebanon Christians strong enough to stop a Hizbollah take over but for Israel its not so clear cut. Israel is focused more on destroying Hizbollah than trying to contain it, so a weaker Lebanon army is better. Bottom like is that these US Congressmen would rather put US troops at risk than IDF soldiers, people in US may not see that way but foreign Gov. do.
Beirut protesters must leave environment ministry, interior minister says (Reuters)
from the article: U.S.: Iran's actions compromise Lebanon's sovereignty