You do so you would be killer your allies? You know group called the kurds? You kinda inforced a no flyzone for decades to protect the. Ring any bells? And now you want to start killing them?
As a general rule nuke a mayor city to someone who is generaly regared as being on you side (you mentioned vitnam you would have lost that a lot sooner if the saudis hand't made sure you had oil to run your equipment)
So quoteing a person in an attempt to support that claim. Ammusing
A natation that forgets it isn't the only one with nukes risks loseing cities. Along with it's existing nuclear arsnel france has about 40 tonnes of plutionium in storage. That is quite a lot of bombs
Allies? you have already advotated nukeing you allies.
We would not of nuked Vietnam in the first place, it would of began war with the Russian (Communists). We were in Vietnam to make a point to the Western Hemisphere here, that Russian plans in Cuba would recieve similar responses. Ring a Bell...that we were playing the mad dog of the Western Hemisphere, that we were making a point, rather then seriously waging a war in Vietnam. It was a political attempt that was similar to our influencial attempts in 1812 with the British. An empty bluff, to signal we were still in control.
Second We are allies with the French, and their attempts to use Nuclear Weapons against us would turn our allies against them. Most of which havea platform for full scale invasion of france: Spain, England, etc. Third They woudl agree that this was a good approach after the terrorist bombings and attacks on their own subways, busses, etc. We have enough support that the French Frogs would stay out of it.
We are not allies with the Muslims as much as we are with the Jews...We protect Israel from them on a constant basis...and so saying that we would not hesistate to attack those other third world countries.
And Quotes like that apply two reasons

1) the majority of the country are babbling idiots that insult people rather then focus on concepts, ideas, or even current events. (2) We value our principles over all else in this country...as a result we offer then to Illegal Aliens, etc. It is by the people choose to purge ourselves of these burdens, to enforce those rights for our citizens rather then provide those rights to anyone.
We are not a country that gives Welfare to the Starving people of another country; we are the Super Power that feeds itself, and dictates to thier leaders that they should spend more time building industry, and growing food...rather then sitting back and complaining that we must make up for their laziness. "You do not work....You do not eat!" famous words of John Smith...apply in full extent to this problem. We dont concern ourselves with the struggles of the world or the problems they have provided themselves with, but instead come in and tell their leaders, that they will not buy another palace or luxury house and put that money towards feeding and supporting their people. If they fail to do this, we tear down the leaders, and convert the country into an indirect establishment, where we train their people to work, and if they refuse, we don't feed them we leave them their to think about it on an empty stomach, until they either starve or work.