In the US this could be a good thing. If Christians don't unite and get involved in politics we will lose the right to express our religion openly. Some fear Catholic domination, but there can still be a basis for cooperation if there is a will to do so.
A big problem with religious leaders in office is that they tend to want to force their views on everybody. Morality can not be legislated. The unintended consequences make the situation worse always.
I believe in the proposition that laws can not be passed prohibiting the free expression of religion. Nor should there be a state religion. I love freedom for everybody. This does not mean that the state and religion should be entirely separate as is commonly stated in this country.
There are no doubt issues in the Philippines that I do not understand properly. Also note that I am a protestant. The answer depends really on the character of the candidate. I do not know to whom you refer.