This Washington Times story mentions the way the current immigration debate may be exposing divisions in both Democratic and Republican coalitions. While summarizing some of the disagreements amongst Democratic members of Congress, it also points out:

there was new evidence last week that Republicans' deepening divisions over immigration are hurting them financially. The annual President's Dinner to raise funds for the House and Senate campaign committees raised $15.4 million, down sharply from the $23 million the event raised in 2005, the most-recent non-election year.