From a recent WSJ poll:
Views of immigration have also become more partisan. In an April 2005 poll that asked whether immigration strengthened or weakened the U.S., a plurality of 48% said it weakened the nation, with 41% saying immigration strengthened the country.
Now, a substantial majority of 64% view immigration as strengthening the country, while 28% say it weakens the U.S. The change is due almost entirely to a sharp shift in Democrats’ views. In 2005, just 45% of Democrats said the country was strengthened by immigration; now the share is 81%.
Democrats also are now more inclined to see globalization as beneficial, compared with 20 years ago, when both parties had largely similar views of the matter.