Texas Governor Greg Abbott caused a stir on Monday after signing an order banning the "sanctuary cities" practice of protecting immigrants across the state. After making the unexpected announcement on Facebook live late on Sunday, Abbott has been criticized by opponents as "cowardly" for the surprise declaration.

"Elected officials and law enforcement agencies don't get to choose which laws they will obey," said Abbott in a short video made as he signed the order. Being a "sanctuary city," refers to a practice in which a local government limits its cooperation with national immigration authorities, usually to protect immigrants from deportation.

Governor Abbott called out Travis County Sheriff Sally Hernandez, whose jurisdiction includes the state capital Austin, a liberal pocket of the staunchly Republican state. She has made police outreach to immigrant communities a cornerstone of her tenure.

"The Travis County Sheriff declares that she would not detain known criminals accused of violent crimes. Those policies are sanctuary city policies. It won't be tolerated in Texas," Abbott said.

However, according to reports, Hernandez's office does indeed cooperate with federal authorities when individuals are suspected of serious crimes. This is Abbott's second gambit against the sheriff: he has already cut off some of her county's budget in response to her attitude towards immigrants.

As sanctuary city is an ambiguous term used differently by varying municipalities, it is hard to count how many there are in the US and compare how their policies differ. Although it generally refers to taking a protective policy towards immigrants and refugees, some cities implement official statutes while others employ de facto "sanctuary" tactics. This makes it equally difficult to say just how Governor Abbott plans to enforce his ban.

ACLU vows immediate legal action

State Congressman Cesar Blanco, who represents the city of El Paso on the Mexican border, told The Washington Post that it was "cowardly," to make the announcement via Facebook on a Sunday night.

"It's ironic that he does it on a Sunday when families are together and this legislation is only going to tear families apart," Blanco said. "I think he wanted to get it done quickly with less friction."

The American Civil Liberties Union (ACLU) in Texas made it clear that they would fight the new law, which goes into effect on September 1.

"We've fought and won against 'show me your papers' laws before, and we will fight again," the non-profit wrote on its official Facebook page, adding that Abbott "just gave police a license to discriminate."

Democratic State Representative Eddie Rodriguez called Abbott's move "extremely personal," according to the Associated Press. "There is a lot of disconnect," between the state house and immigrants in Texas, he added.

For immigrants without paperwork, something as simple as a traffic stop can see them deported back to their home countries - many need to drive for their work, but cannot legally obtain driver's licenses without US identification. This can be catastrophic for families when one parent is caught driving without a license.

Mexican immigration dropping

Although migration from Mexico has been on a downward trend for years, capitalizing on fears of illegal immigration helped propel US President Donald Trump into the White House. The president has made repeated promises to curb immigration to the US, even as his attempts at a travel ban against Muslim-majority countries were declared unconstitutional by the courts and his bid to secure funding for a border wall with Mexico - a key campaign promise - was met with skepticism by both congressional Republicans and Democrats.

President Trump tried to sign an executive order cutting funding to sanctuary cities at the end of April, but that too was blocked by a federal judge in California.

Texas has long history as a focal point of immigration because of its border with Mexico. According to the Migration Policy Institute, a nonpartisan think tank, Texas is second only to California in the number of immigrants who were born in Mexico. On top of this, migrants from Central and South America often try to enter the US illegally on foot via the Texas-Mexico border, despite the large patches of fencing and dangerous terrain.