Sixteen Democratic senators want the Justice Department to look into whether voting rights are being jeopardized in states that require photo identification in order for people to vote.
The lawmakers wrote Attorney General Eric Holder on Wednesday to express concern that millions of voters do not have a government-issued ID _ particularly older people, racial minorities, low-income voters and students.
The senators say the photo ID requirements have the potential to block millions of eligible people from exercising their right to vote.
Justice Department spokeswoman Tracy Schmaler said the department is monitoring, as it routinely does, this type of legislative activity in the states.
"We urge you to protect the voting rights of Americans by using the full power of the Department of Justice to review these voter identification laws and scrutinize their implementation," the senators said in the letter to the attorney general.
The 16 senators include Senate Majority Leader Harry Reid of Nevada, Michael Bennet of Colorado, Chuck Schumer and Kirsten Gillibrand of New York, Dick Durbin of Illinois, Patty Murray of Washington, Mary Landrieu of Louisiana, Sherrod Brown of Ohio, Ron Wyden and Jeff Merkley of Oregon, Jeanne Shaheen of New Hampshire, Benjamin Cardin of Maryland, Mark Begich of Alaska, Tom Harkin of Iowa, Herb Kohl of Wisconsin and Tom Udall of New Mexico.
"Many of these laws effectively disenfranchise thousands of eligible voters," Bennet said in a statement.
The senators are seeking vigorous enforcement of the Voting Rights Act and federal civil rights law, which bars different standards from being applied to individuals within a jurisdiction. Section 5 of the Voting Rights Act gives the Justice Department significant authority to review laws before they are implemented in states with a history of discriminatory voting practices. Three states subject to Section 5 _ Georgia, Texas and South Carolina _ require a photo ID in order to vote. Texas and South Carolina enacted their laws last month.
Other states with a photo ID requirement are Indiana, Wisconsin, Kansas and Tennessee, according to the Ohio State University Moritz College of Law, which gathers data nationally on election law.
Florida, Hawaii, Idaho, Louisiana, Michigan and South Dakota have voter photo ID requirements, but they do not necessarily prevent voters from casting ballots, according to the data gathered by the Moritz school. Voters may, for example, sign an affidavit in place of a photo ID.
Other states where the issue is pending or where such proposals were recently rejected:
_In Minnesota, Missouri, New Hampshire and North Carolina, Democratic governors vetoed legislation.
_In Pennsylvania, state House Republicans pushed through a mandate this month that Pennsylvania voters have a government-issued photo ID. The measure was sent to the state Senate.
_In Ohio, the state House passed a bill to require voters to show a photo ID at the polls. The measure will likely be considered in the GOP-controlled Senate this fall.
Photo IDs are not the only controversial issue in the realm of voter requirements.
In Arizona, minority groups are in court challenging a state law that requires people to show proof of citizenship when they register to vote. The U.S. Justice Department urged the courts to overturn the Arizona law, saying it conflicts with the National Voter Registration Act. That federal law allows people to submit a mail-in voter registration card and swear they are citizens under penalty of perjury.