Why do you think plunkitt was willing to people of his district at all hours of the day and night

He claimed that if he did all that it would be helpful for both the people and him. He believed that if you are a politician, you work for yourself and in your self-interest. If you find a way to help yourself and at the same time your people and your country, that would be the best, so being available for help was a political move that would help elevate his rank, while also being used for the people.

Hope this helps! :) 

If he breaks the law then he had to resign from his post and so he'll lose his/her powers.