Gerrymandering is an issue, but it's actually the solution to greater problems. Gerrymandering itself is performed by elected officials who, again, are responsible to their constituency. The practice can be seem undemocratic, but the two party system is an eventuality, if one party starts gaining too much power and popularity then people will just start joining that party which will create a schism which will in turn create another party. We cannot guard against a two party system.