pork-barrel politician; special-interest politician
A politician who acts as a lobbyist for specific industries or interest groups, often securing government benefits for them. The term carries a critical nuance of collusion between politicians and private sectors.
Due to the influence of pork-barrel politicians, subsidies for that industry increased.
He is known as a pork-barrel politician for the construction industry.
圧力団体 is a pressure group or lobby, whereas 族議員 is an individual politician who acts on behalf of such groups.
Compound of 族 (ぞく, 'tribe' or 'group') and 議員 (ぎいん, 'legislator'). The term emerged in Japanese political discourse to describe lawmakers who form informal 'tribes' aligned with specific industries.