Texas' strict new immigration law giving state police powers to arrest people on suspicion of illegally crossing the Mexico border was back on hold late Tuesday, hours after the U.S. Supreme Court allowed it to take effect.

The latest: A federal appeals court temporarily blocked the law, known as SB 4, from taking effect in a 2-1 order late Tuesday.

Context: The Supreme Court's majority ruling didn't uphold the law but briefly cleared the way for the state to begin enforcing the measure.

• That was until the 5th U.S. Circuit Court of Appeals' order temporarily put the law back on hold ahead of hearing legal challenges against it on Wednesday.
• One panel member, Circuit Judge Andrew Oldham, dissented, saying: "I would leave that stay in place pending tomorrow's oral argument on the question."

Why it matters: The law was challenged by the Department of Justice over concerns that it encroached on the federal government's authority over immigration and by immigration advocacy organizations that have said it could lead to racial profiling.

• The Supreme Court's decision marked a victory for Texas Gov. Greg Abbott (R) and his fellow Republicans, who have made the recent increase in illegal crossings at the U.S.-Mexico border a central issue in the 2024 elections.

Flashback: The Supreme Court temporarily blocked the law earlier this month, extended that hold last week and issued an indefinite block on Monday.

What's inside: Because Tuesday's ruling was in response to an emergency application, the court did not explain its reasoning for lifting the hold and allowing the law to be enforced.

• However, Justice Amy Coney Barrett, joined by Justice Brett Kavanaugh, said in a concurring opinion that they were returning the case to an appeals court, which should rule on whether Texas should be allowed to enforce its law before challenges are resolved.
• The court's three liberal justices dissented to Tuesday's ruling.
• Justice Sonia Sotomayor, joined by Justice Ketanji Brown Jackson, warned in a dissenting argument that the court "invites further chaos and crisis in immigration enforcement" by lifting the hold.
• Sotomayor further warned that the law "upends the federal-state balance of power that has existed for over a century, in which the National government has had exclusive authority over entry and removal of noncitizens."

What we're watching: Mexico's Foreign Ministry said in a statement condemning Texas' law Tuesday it "categorically rejects any measure that allows state or local authorities to exercise immigration control, and to arrest and return nationals or foreigners to Mexican territory."

• Mexico's government opposes the Texas law and said it would "file a friend-of-the-court brief" to the federal appeals court in Louisiana that's hearing legal challenges against the legislation.

How it works: The law makes it a state crime to illegally cross the Texas-Mexico border between ports of entry and allows state police to arrest people if the authorities have probable cause to believe they did so.

• Those arrested can be charged with a misdemeanor that carries a punishment of up to six months in jail and could face felony charges and up to 20 years in prison for subsequent offenses.
• It also requires law enforcement to collect identification information of those they arrest, such as fingerprints and photographs, and grants judges the power to order an undocumented person to return to Mexico.

Zoom in: The law also ignited concerns among immigration advocates over whether it would be used to target anyone without a legal immigration status, even if they've been living in the state for years.

• In Texas, crimes classified as misdemeanors have a statute of limitations of two years, while felonies have a statute of limitations of up to three years.

Caveat: The law does prevent police from arresting people in certain settings, such as in public or private schools, places of worship, hospitals and other health care or medical forensic facilities.

• College or university campuses are not included among those settings.

Go deeper: Supreme Court extends hold on Texas immigration law

Editor's note: This story has been updated with comment from Mexico's government, details of the 5th U.S. Circuit Court of Appeals ruling, and corrected to say the Supreme Court issued Tuesday's decision by a majority vote, not 5-4.