By David G. Savage

A deadlocked Supreme Court could not rule Thursday on the legality of President Obama's immigration reform plan, leaving in place a lower court's order in Texas that blocked it from taking effect.

The 4-4 tie vote deals a severe blow to the president's initiative and denies deportation relief and work permits to more than 4 million immigrants who have been living in this country illegally.

The justices issued a one-line decision saying the judgment of the lower court "is affirmed by an equally divided court."

The split was almost certainly along the familiar ideological lines, though the justices' votes were not revealed.

During oral arguments in April, the four conservative justices, all Republicans, had voiced support for the lawsuit by Texas and 25 other Republican-led states, who said Obama's order was illegal.

The four liberal justices, all Democratic appointees, appeared to favor the administration and its claims that the president has broad power under immigration law to set enforcement policies.

In this instance, the president contended that deportations should focus on criminals, gang members and people who repeatedly cross the border, but not on immigrant parents of U.S. citizens.

Obama proposed to allow people who fit this category to come forward, undergo a background check and receive a work permit if they qualified. It was similar to a previous program that benefited immigrants who were brought to the U.S. illegally as children, dubbed "Dreamers." That program is unaffected by Thursday's ruling.

Texas state lawyers said Obama's second immigration-reform plan went too far. They sued in a federal court in Brownsville. A judge issued a national order preventing Obama's plan from going into effect, and the 5th Circuit Court in New Orleans upheld that order.

Thursday's vote means the fate of Obama's immigration policy will be decided next year by a new president and possibly by a nine-member Supreme Court. The February death of Justice Antonin Scalia has left the court ideologically divided, and the GOP-controlled Senate is refusing to vote on Obama's nominee, Judge Merrick Garland.

Until Thursday, supporters of Obama's immigration plan hoped that Chief Justice John G. Roberts Jr. or one of his conservative colleagues would vote to throw out the Texas suit. In the past, the conservatives have been skeptical of states suing to challenge federal initiatives. They have questioned whether the states have standing to sue.

But in recent years, conservatives also have been troubled by Obama's willingness to use his executive authority to make changes in response to deadlock on Capitol Hill. They accused the president of overstepping his authority, and those concerns were widely voiced when the immigration dispute moved into the court.

Critics note that the president conceded he took action on immigration only after the Republican-controlled Congress failed to approve an immigration reform plan. Texas lawyers insisted that only Congress, not the president, could change the immigration laws.

In December, the conservative justices signaled their leanings when they said they would consider whether the president had failed in his constitutional duty to "faithfully" execute the laws.

But Scalia's death left the court's conservatives without a solid majority to rule more broadly and possibly rebuke the president directly.

Nevertheless, Republicans praised Thursday's outcome.

"The Supreme Court's ruling makes the president's executive action on immigration null and void," said House Speaker Paul D. Ryan (R-Wis.). "The Constitution is clear: The president is not permitted to write laws _ only Congress is. This is another major victory in our fight to restore the separation of powers."

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