Consider the idiom develop a tin ear in its most figurative sense, the one you use when you want to say that someone has fallen short or become oblivious of their promises, duty, or line of conduct in behalf of their own ends.
Public servants come to the capital full of pure intentions and then, it is said, fall into the orbit of special interests and develop a tin ear to the cries of constituents.
What's most troubling is that President Obama seems to have developed a tin ear about shadow money in politics.
Alternately, look the other way might fit here.
look the other way: (fig) to ignore something on purpose, especially something of an illicit nature.
E.g. The usher decided to look the other way when the little boy sneaked into the theater