Consider the following premises. For all x_7, if x_7 were a politician, then x_7 is drinking water. There is at least one x_7 for which x_7 is a politician if and only if x_7 will drink water. Can we infer the following from them? For all x_7, the fact that x_7 were a politician does not imply that x_7 is drinking water.
That contradicts the premises. Therefore the answer is no.