Split US Supreme Court blocks Obama immigration plan

The Obama administration could ask the high court to rehear the case, as losing parties in two other cases in which the court has split 4-4 have done. The court has not yet acted on those other petitions.

The states argued that Obama overstepped the powers granted to him by the US Constitution by infringing upon the authority of Congress.

"Today's decision keeps in place what we have maintained from the very start: one person, even a president, cannot unilaterally change the law. This is a major setback to President Obama's attempts to expand executive power, and a victory for those who believe in the separation of powers and the rule of law," said Texas Attorney General Ken Paxton, a Republican.

Republican US House of Representatives Speaker Paul Ryan said the ruling "makes the president's executive action on immigration null and void." Ryan described the decision as a "major victory in our fight to restore the separation of powers."

The Constitution assigns certain powers to the executive, legislative and judicial branches of the federal government.

The court did not issue a ruling on the merits of the main legal question. Therefore, its action set no legal precedent to bind future presidents. The decision indicates that any major immigration policy change that would address the long-term situation of the estimated 11 million people in the country illegally would have to be enacted by Congress.

This was not the first time that the Supreme Court determined the fate of an important Obama initiative. The justices in 2012 and 2015 issued high-profile rulings preserving his signature healthcare law that Republicans have long fought.