WASHINGTON — The Supreme Court dealt a likely fatal blow Thursday to President Obama's effort to protect millions of undocumented immigrants from deportation and allow them to seek work permits, deadlocking 4-4 over a plan that had divided the nation as well as the justices.

The tie vote leaves intact a preliminary injunction that stopped the program in its tracks more than a year ago, after Texas and 25 other states claimed Obama lacked the authority to circumvent Congress. While the case now will return to Texas for further review, it's {highly} unlikely the lower federal courts that blocked the program will reverse themselves.

In practical terms, then, the 4-4 vote dooms for the remainder of Obama's presidency his goal of providing protection to more than 4 million undocumented parents whose children already have such protection. The justices likely split along ideological lines, though the vote was not revealed; the ruling carries no national precedent.

It was a sudden, crushing defeat for millions of parents who came to the country illegally and have lived in the shadows, often for decades. The administration had hoped that at least one of the more conservative justices — possibly Chief Justice John Roberts — would rule that the plan posed no financial threat to the states and therefore could not be challenged in court.......