What is SB4? The controversial Texas immigration law explained

A federal appeals court has issued an order preventing Texas from arresting migrants suspected of entering the country illegally. The order came hours after the Supreme Court gave the state the green light to enforce its controversial new immigration law.

The SB4 law makes it a crime for individuals to cross the US–Mexico border illegally and giveslaw enforcement the authority to charge them with a Class B misdemeanour, which carries a maximum sentence of six months in jail. Second offenders could face second-degree felony charges and up to 20 years in prison.

The decision to block the law by the 5th US Circuit Court of Appeals comes weeks after a panel on the same court cleared the way for Texas to enforce it.

But a majority verdict by a three-judge panel of the appeals court late on 19 March ruled that the law should still not be enforced until further arguments are made before the court.

The Texas authorities had not announced any arrests made under the law while it was briefly enforceable.

The temporary order comes as a blow against Texas Governor Greg Abbott, who has championed the need for aggressive legislation to deter migrants from crossing the border, with tough penalties for those who do so.

The bill, which Mr Abbott signed in December, was set to go into effect earlier this month. The Justice Department as well as immigration advocacy groups petitioned federal courts to intervene and prevent the law from taking effect in the meantime.

The Biden administration then asked the Supreme Court to stay the law, which it did earlier this month and again last week.

But earlier on 19 March, the conservative majority on the top court said they would wait to issue a formal ruling or opinion on the emergency order until