In the survey, 63 percent of Republicans under 30 said they supported giving those immigrants a chance to become citizens if they met certain requirements. Only 20 percent of young Republicans said they would identify and deport them. By contrast, about a third — 34 percent — of Republicans age 65 and over favored deportation, and less than half — 47 percent — said they supported a pathway to citizenship for those immigrants.

A third option, allowing the immigrants to become permanent legal residents but not citizens, was not supported by more than 15 percent of either group.

The institute’s survey is unusual because of the size and duration of its sample. The report is based on 42,586 telephone interviews conducted in English and Spanish from April 29, 2015, to Jan. 7, 2016. The margin of error is plus or minus one point.