[This update taken from the SCOTUSblog]
The Texas law was first passed five years ago, but has been under continuous challenge, and has been found unconstitutional as racially discriminatory by three federal courts — a federal trial judge and two unanimous three-judge panels of the Fifth Circuit. However, the law has continued in effect because of temporary orders permitting enforcement, including one by the Supreme Court in October 2014, dividing the justices six to three. (That Court action was released shortly after 5 a.m., following an all-nighter by Justice Ruth Bader Ginsburg, who stayed up through the night writing her dissenting opinion.)
Each time the challengers have gone into court to try to put the ID law on hold, they have argued that some 600,000 Texans — mainly, black and Hispanic voters who otherwise are eligible to vote — do not have the kind of identification documents that would satisfy the strict law. The Supreme Court dissenters also relied on that argument when the Court left the requirement in effect for the November 2014 elections.
The latest three-judge Fifth Circuit ruling against the ID law has been set aside while the full Fifth Circuit conducts its own review. A hearing is set before the en banc Fifth Circuit on May 24 which also happens to be the date of the primary run-off election in Texas. Veasey v. Abbott was filed with Justice Thomas seeking Supreme Court action to block the ID requirement and compel the state to start taking the steps necessary to prepare for a November election without the requirement. The state could remain flexible in its arrangements, the application argued, in case the ID mandate were upheld by the en banc Fifth Circuit.