This paper will attempt to explain why the European Parliament has been taking an increasingly restrictive position on immigration since 2005, and particularly after the 2009 ratification of the Lisbon Treaty (which increased the authority of the Parliament in the field of immigration). The author will argue that one must go beyond parliamentary demographics, changing public opinion, or ideology and examine the EU’s political structure to obtain an adequate explanation. The Parliament’s views on immigration appear to be closely linked to institutional dynamics and a desire to respond to criticism that EU institutions suffer from a “Democratic Deficit”. This study will demonstrate that the large change in voting behavior of the EP in the field of immigration, determined by analyzing EP voting behavior on legislation before and after 2005, appears to be due to the change of authority of the EP (on immigration legislation) from Consultation to Co-decision in 2005. Specifically, regression analysis relating voting behavior and party affiliation indicates that a significant decrease in both party cohesion and support for a liberal policy occurred after 2005, particularly with two of its main parties, the S&D and ELDR. As the Parliament, like other EU institutions, attempts to be more democratic and thus more responsive to the concerns of their constituencies, one can speculate that the views expressed by the Parliament in areas besides immigration will increasingly coincide with those expressed by the Council and the Commission.