What's a good idiom or phrase that expresses that someone is corrupt and is working for a company or someone? There are political shows where it was used, but I don't remember exactly what the expression was, so I am wondering if someone knows what the phrase or idiom might be or know another idiom or phrase than the one I forgot about.
There is the idiom in somebody’s pocket. TFD defines it like this:
in (one's) pocket
Under one's control or influence, especially in an underhanded or unethical way, such as by bribery or extortion.
It's pretty obvious that our national legislators are all in corporate bigwigs' pockets!
I hear that the boss has half the police force in his pocket.
Here is the expression used in a 2010 article from The Atlantic:
Democrats have been accusing Republicans of being in Big Oil's pocket for years, ever since Vice President Dick Cheney's energy policy task force.
and here’s another example from Time (2014):
D.C.'s teachers union spent $1 million to defeat the mayor who appointed her and elect a corrupt mayor who is in the union's pocket.
Such a person can be said to have a hidden agenda:
A secret or ulterior motive for something.
‘They want to be certain that government officials don't have a hidden agenda.’
‘But nothing concrete is happening, and the politicians are busy pursuing their own goals and hidden agendas rather than focussing on peace and security in the country.’
(source: Oxford Dictionaries)