The whole idea of neutron bombs was so abhorrent to Ed Teller that he refused to help, effectively killing any US efforts in that direction.
After that, any putative US neutron bomb in existence would have been eliminated from the US arsenal under Clinton during his crippling purge of US nuclear capabilities.
US nuclear capabilities are a shadow of what they were in the 1970s and 80s. In fact, there is a reasonable supposition that many current warheads may not work, due to age and lack of actual testing - the only testing done today is via simulation aka computer models - we all know how well that works for the climate changers.
If we have worse, we will only know that capability when and if the situation arises of use it or lose it.
As far as Israel having a neutron capability, it is only rumor and supposition. Again, without actual testing, there is no way to be sure that an existing warhead will actually work - assuming that Israel once had a working warhead or a prototype.
The only country known to have once had working, tested (in the late 1990s) neutron warheads is China - something we likely have Clinton to thank for as part of his Third Way philosophy.
Same reasoning applies to the assumed Israeli nukes.
http://en.wikipedia.org/wiki/Neutron_bomb
By 1984, according to Mordechai Vanunu, Israel was mass-producing neutron bombs.[23] A number of analysts believe that the Vela incident was an Israeli neutron bomb experiment.[24]
http://en.wikipedia.org/wiki/Vela_Incident
http://en.wikipedia.org/wiki/Israel_and_weapons_of_mass_destruction
China Test-detonates Kiloton Neutron Bomb
http://uts.cc.utexas.edu/~wbova/fn/gov/china_nb.htm