Voter ID laws have swept across the country. (Melina Mara/THE WASHINGTON POST)

The fight over voter ID is almost entirely along party lines.

Republicans argue that voter ID is a necessary protection against voter fraud while Democrats counter that fraud is used as an excuse to suppress turnout among elderly, poor and minority voters who may have more difficulty obtaining proper ID. (Evidence of widespread fraud is scant.)

Here’s an update on where it stands, across the country.

Since the 2010 election, eight states have passed laws requiring voters to carry identification: Alabama, Kansas, Pennsylvania, Mississippi, Rhode Island, South Carolina, Tennessee, Texas and Wisconsin. Twenty-seven states already had voter ID laws on the books before 2011.

* The new voter ID law in Kansas may face a court challenge. A last-minute push to also require proof-of-citizenship from new voters doesn’t take effect until January 2013. Secretary of State Kris Kobach (R) is trying to fast-track it for the November election but legislative leaders say they don’t have time to act on his proposal.*

* In Minnesota, a proposed constitutional amendment requiring voter ID is close to passing in the state legislature. Gov. Mark Dayton (D) vetoed voter ID legislation last year but cannot block a constitutional amendment. Polling suggests it will pass.

* In Mississippi, officials are moving ahead with a voter ID law similar to the one blocked in Texas. Federal officials say they are waiting for legislation to implement the law before weighing in. The Justice Department has the power to block voting laws in Alabama, Alaska, Arizona, Georgia, Louisiana, Mississippi, South Carolina and Virginia due a history of minority disenfranchisement.

* Texas’ voter ID law was blocked by the Justice Department on the grounds that it would keep a disproportionate number of Hispanic voters from the polls. But Gov. Rick Perry (R) is pledging to challenge that decision in the Supreme Court.

* The Justice Department rejected South Carolina’s new voter ID law in December; the state is suing the federal government in response.

* A judge in Wisconsin temporarily blocked that state’s new voter ID law earlier this month, and a week later another judge filed a permanent injunction against the law, declaring it unconstitutional. The state attorney general is appealing both decisions.

Pennsylvania’s voter ID law just passed last week and has not yet been challenged in court. Alabama’s new law does not go into effect until 2014. The laws in Kansas, Tennessee and Rhode Island have not been challenged.

* Virginia’s General Assembly has also passed a voter ID law, but it is less stringent than other legislation (many forms of ID, including utility bills, are allowed) and thus expected to face less opposition.

In Alabama, South Carolina and Texas, laws requiring non-photo ID were already on the books; the new laws require picture IDs. (The National Conference of State Legislatures has a very nifty map.)

All but two of the eight voter ID laws passed since 2011 came from Republican-controlled state legislatures and were signed by Republican governors. (In Mississippi, the Democrat-held House passed voter ID; in Rhode Island Democrats control the legislature and Gov. Lincoln Chafee is an independent.)

Many of the state lawmakers who wrote voter ID legislation have ties to American Legislative Exchange Council (ALEC), a conservative group.

According to the Brennan Center for Justice, the new laws could make it more difficult for up to 5 million Americans to vote. A study done in 2007 found that voter ID laws did not affect turnout; another found the data inconclusive. But opponents argue that in a very close election, any effect would be too much, while advocates counter than even sparse fraud must be prevented.

And should Texas’ case go to the Supreme Court, the effect could go beyond voter ID to impact the Voting Rights Act itself.

* This article erroneously stated that the new Kansas law did not take effect until 2013; the photo ID requirement is in effect, while the proof-of-citizenship requirement takes effect next year. It has been corrected.