About 60 percent of Republicans in a Washington Post poll said they think the nation's illegal immigrants should be able to gradually earn their citizenship, a centerpiece of a new immigration reform blueprint proposed in the Senate.

But when President Barack Obama is mentioned, much of that Republican support vanishes.

When the question mentions that Obama proposed the path to citizenship, only 39 percent of Republicans said they backed such a move. Overall, 59 percent of Americans of both parties support the path to citizenship if Obama is part of it, while 70 percent do when Obama is left out of it.

The polling suggests that the more closely associated the president is with immigration reform, the harder it might be for Republicans to drum up conservative support for a bill. Obama campaigned on passing immigration reform in his second term and will almost certainly stump for the issue in his State of the Union speech Tuesday night.