National Guard troops have been deploying to the southern border for decades after orders by presidents and governors from both parties. In 2010, the Democratic governor of New Mexico at the time, Bill Richardson, ordered a few dozen troops to his state’s border with Mexico after the killing of an Arizona rancher.
But Mr. Trump’s mobilization, which could deploy thousands of troops, has reignited concerns in Texas and elsewhere about the militarization of border communities and has angered local officials and lawmakers who say that the troops are not needed and that they give the false impression that their cities are under siege.
“It sounds to me more like political rhetoric than something that is actually needed on our border,” said Representative Vicente Gonzalez, a Texas Democrat whose district includes the border city of McAllen. “For example, McAllen is at a 32-year low in crime. We’re at a 46-year low in illegal entries. It’s the wildest thing in the world for us to hear that they want to bring National Guard troops to the border region.”
Mr. Trump and federal officials said the troops were needed to help the United States Border Patrol address what Mr. Trump said was a growing threat of unauthorized immigrants, drugs and crime from Central America.
General Norris said on Friday that the troops would be armed for self-defense “depending on the mission set,” and that it was “premature right now to know what the cost will be” of the overall operation.
The deployment is a federal initiative that will be managed by the state, a hybrid known as Title 32. In that capacity, a governor retains control of the National Guard troops but the federal government finances the operation.
General Norris said that in addition to the 250 troops being deployed in the coming days, an unknown number of others would likely be called up as part of a “follow-on phase.”
The response from Texas officials, coming just three days after Mr. Trump called for militarizing the border, was no surprise. Republican leaders in Texas have been outspoken in condemning cartel-related crime, drugs, violence and human smuggling on the border. In fact, they had moved to put the National Guard on the border years ago.
Even as Mr. Trump announced his mobilization this week, the Texas National Guard already had about 100 troops at the border, as part of a state border-security operation that began in 2014. Texas officials dispatched 1,000 National Guard troops to the border because they said drug cartels were taking advantage of the federal government’s focus on the tens of thousands of Central Americans flooding the border at the time.
The deployment was meant to “help combat the brutal Mexican drug cartels that are preying upon our communities,” Rick Perry, then the governor, said in 2014.
The mobilization was supposed to end the following year but was extended by Mr. Perry’s successor, Greg Abbott. State lawmakers said last year that the cost for the National Guard deployment and Texas Military Forces expenses on the border was nearly $63 million.
The 100 National Guard troops who have been at the border play a supporting role to state and federal law enforcement, acting, as state officials describe it, as a “force multiplier.”
“We stand ready to support the needs of the state and the nation at the request of the governor or the president,” Lt. Col. Travis Walters, a spokesman for the Texas Military Department, the agency that oversees the state’s National Guard branches, said in a statement.