Rep. Luis Gutierrez (D-Ill.) warned President Barack Obama on Tuesday that Latinos will not regard as "acceptable" a move to make the E-Verify system of checking prospective employees' immigration status mandatory for all U.S. firms, as urged by Republicans.

Gutierrez, the Chicago-born son of Puerto Rican parents, gave the warning at a telephone press conference ahead of Wednesday's hearing of the House Subcommittee on Immigration Policy and Enforcement about a bill to impose E-Verify nationwide.

That bill is being pushed by the chairman of the House Judiciary Committee, Texas Republican Lamar Smith, and Immigration Subcommittee Chair Elton Gallegly (R-Calif.).

E-Verify, in force since 1997, has been harshly criticized by unions and pro-immigrant groups that say it criminalizes immigrants and is ineffective.

If the measure is passed by the Republican-controlled House of Representatives, it will depend on the Senate, where Democrats are in the majority, for Smith's controversial bill to be approved.

"The danger exists" that the most conservative Democratic senators will support the measure, Gutierrez acknowledged Tuesday, urging Obama to promise he will veto the bill, if necessary.

"The president's Hispanic advisors must make him understand that signing such a proposal before the 2012 elections is not acceptable to the Latino community," the congressman said, stressing the importance of the Hispanic vote for Obama's reelection.

E-Verify allows businessmen to consult databases of the Department of Homeland Security and the Social Security Administration to check whether job applicants have the legal authorization to be hired.

Hispanic activists complain that the system is "riddled with errors," so that it affects legal immigrant workers more than the undocumented.

That was explained Tuesday by the executive director of the National Immigration Law Center, Marielena Hincapie, who said that naturalized citizens and Green Card holders are up to 32 times more likely to figure as "not authorized" for working than U.S.-born jobseekers.

Another of the most criticized aspects of this program is just how effective it will be in achieving its purported objective of reducing unemployment among citizens and legal residents.

Critics say that the true intention of Smith's bill is to use the immigrant community as a scapegoat.

So says Gutierrez, who believes Republicans "have the false hope that the 11 million undocumented workers and their families will leave if we make things difficult. That's a fantasy. They're not going to leave, they have their life here," he said.

Southern states like Alabama, Georgia and Tennessee have already approved laws making E-Verify obligatory in their territory.

In addition, the U.S. Supreme Court ruled on June 6 that states may oblige companies to use E-Verify.