That’s like saying that the USA is no more an ally to the UK or Canada or several other NATO members than China, Russia or Iran is to these same countries.
AND ... that certainly must be true about the USA towards its “so-called allies” (in name only and not ‘in fact’ - in other words) ... BECAUSE ... Obama is certainly going out of his way to PROVE THAT to these “in name only” Allies ... :-) ...
Believe me these “so-called” and “in name only” Allies are certainly believing EXACTLY AS YOU SAY ... but in regards to the USA ... LOL ...
No, it's not. The U.S. has a mutual defense treaty with Great Britain and Canada that it does not have with China, Russia or Iran. This means the U.S. has a formal obligation to commit military resources to assist Great Britain and Canada when needed, but has no such obligation to Russia or China.
The U.S. has no similar obligation to Israel, either.