Is it a good idea for Christians to get involved in politics, because if they are involved in it, they tend to lie, make promises they can't fulfill and sometimes get their hands dirty which is sin.
Remove "Christian" and replace it with "Muslim" or "Jewish", etc and there's your answer. EVERYONE should be engaged in politics imho and everyone should be free to run provided they qualify for the position. Then it's just a matter of making sure they keep their religious/ethnic biases out of their decision-making and that they not give preferential treatment to their "kind".
And ministers of the Gospel, are they suppose to endorse any candidate to their congregants. What's your take?
No. We've barred doctors from endorsing brands in ads because of possible conflicts of interest, the same should apply to other "professionals," including the clergy.