WASHINGTON—The Obama administration, unable to push an immigration overhaul through Congress, is considering ways it could go around lawmakers to let undocumented immigrants stay in the United States, according to an agency memo.

The internal draft written by officials at U.S. Citizenship and Immigration Services outlines ways the government could provide "relief" to illegal immigrants -- including delaying deportation for some, perhaps indefinitely, or granting green cards to others -- in the absence of legislation revamping the system.

It's emerging as chances fade in this election year for a measure President Barack Obama favors to put the nation's estimated 12 million undocumented immigrants on a path to legal status, and as debate rages over an Arizona law targeting people suspected of being in the country illegally.

The 11-page internal memo, written in April to the agency's director, says: "This memorandum offers administrative relief options to promote family unity, foster economic growth, achieve significant process improvements and reduce the threat of removal for certain individuals present in the United States without authorization."

It goes on: "In the absence of comprehensive immigration reform, USCIS can extend benefits and/or protections to many individuals or groups."

The memo drew a backlash by Republicans who called it evidence that Obama is looking for ways of relaxing immigration policies without political consensus to enact a new law.

"The document provides an additional basis for our concerns that the administration will go to great lengths to circumvent Congress and unilaterally execute a backdoor amnesty plan," said Sen. Charles Grassley, R-Iowa, who obtained and circulated the memo. "The problem remains that if you reward illegality, you get more of it."

Grassley led a group of conservative GOP senators who wrote to Obama in June asking him to promise that the administration wouldn't use its authority to "change the current position of a large group of illegal aliens already in the United States."

The Iowan's staff said the group has not received a response.

"Now we find out the truth: While saying one thing to the public, the Obama administration is scheming to ensure that immigration laws are not enforced," said Rep. Lamar Smith of Texas, the top Republican on the House Judiciary Committee.

Administration officials sought to downplay the memo's significance, saying it was merely the product of brainstorming sessions and noting that many of the ideas it suggests were first discussed when George W. Bush was president, after his immigration overhaul died in Congress in 2007.

Agency spokesman Christopher Bentley said the internal document "should not be equated with official action or policy," and represented only "deliberation and exchange of ideas."