Immigrants and permanent residents have representation, as do felons.

Congresspeople represent all the residents of their district, not just the citizens. While non-citizens are not allowed to vote on their choice of representative, they are allowed to call their local congressperson and express their opinions on upcoming legislation, and can volunteer in political campaigns. Permanent residents are also allowed to donate money to political campaigns.

At least in CA and NY, non-citizens do regularly take advantage of their rights within the US political system.