The order has been issued for the immediate construction of a Mexico border wall. The specs have been outlined: 30 feet high and “aesthetically pleasing.” The next thing on President Trump's to-do list for building his “big, beautiful wall”: Hire more lawyers for a long and expensive battle over private land.

The wall will cost a lot more — politically and economically — than Trump has publicly acknowledged. To build the wall along the nearly 2,000-mile border — and fulfill a key campaign promise — Trump will need to wield the power of government to forcibly take private properties, including those belonging to his supporters.

Much of the border, especially in Texas, snakes through farms, ranches, orchards, golf courses, and other private property dating back to centuries-old Spanish land grants. As a signpost to the troubles ahead, the government has still not finished the process from the last such undertaking a decade ago.

“It's going to be time consuming and costly,” said Tony Martinez, an attorney who is mayor of the border town of Brownsville, Tex. “From a political perspective, you have a lot of rich landowners who were his supporters.”

Trump, in his recent budget proposal, is calling for the addition of 20 Justice Department attorneys to “pursue federal efforts to obtain the land and holdings necessary to secure the southwest border.” The Justice Department would not expand upon the details. Of the department's 11,000 attorneys, fewer than 20 currently work in land acquisition. Trump's budget would double that.

The battle has been fought before. The last wave of eminent domain cases over southern border properties dates back to the 2006 Secure Fence Act authorizing President George W. Bush to erect 700 miles of fencing.

Of the roughly 400 condemnation cases stemming from that era, about 90 remain open a decade later, according to the Justice Department. Nearly all are in the Rio Grande Valley in southwest Texas.

The U.S. government has already spent $78 million compensating private landowners, as well as on land surveys and appraisals, for 600 tracts of property for the construction of the existing pedestrian and vehicle fence, according to Customs and Border Protection. The agency estimates that it will spend another $21 million in real estate expenses associated with the remaining condemnation cases — not including approximately $4 million in Justice Department litigation costs.

A 2009 Homeland Security inspector general report highlighted the difficulties in acquiring the necessary land: “Gaining access rights … delayed the completion of fence construction and may increase the cost beyond available funding.”

Researchers and lawyers say eminent domain will continue to be a big issue for Trump, one that could even stymie his ambitious plans for an “impenetrable” wall.

“It will be a huge challenge for his administration. It will clog up the courts,” said Terence Garrett, a security studies and public affairs professor at the University of Texas Rio Grande Valley in Brownsville. “It’s just an affront to property rights.”

The university became embroiled in the land dispute in 2007 when the federal government sought to build an 18-foot-high wall that would have divided the campus in two. Students would have had to obtain land crossing cards to go back and forth across campus, even though they were still in the United States, Garrett said.

The university and government ended up compromising on a “pleasant looking” 10-foot-high fence that cut off the city golf course adjacent to campus, said Garrett, who served as a strategist for the university president during the lawsuits. The golf course ended up going out of business.

“All the grass has grown up around it and it’s, in a sense, ceded back to nature,” Garrett said.

But the fence provides a “false sense of security,” he said. People can easily climb over it. And it’s not continuous.

About 10 miles west of the university is another Brownsville golf course — the River Bend Resort & Golf Club that at the time managed to convince the Bush administration not to build on its property. The existing rust-colored border fence abuts the golf club’s eastern and western edges, but leaves a 1.7 mile gap in between.

The golf course’s new owners, who bought the club in 2015, say a wall running through the course would be disastrous for business. Fifteen of its 18 holes — and more than 200 homes — would be on the south side of the levee, where the wall would be constructed, said Jeremy Barnard, River Bend’s general manager whose father and uncle own the resort.

If the wall were to be built following its existing path along the levee, 70 percent of the 319-acre resort would be relegated to a sort of no man’s land between the levee and the natural border of the Rio Grande River, he said.

“My goal would be to get Trump out to play the course, appealing to the golf course owner and business side of him, and say, ‘Look, what would you do?’ ” Barnard said. “Seven of our holes are on the Rio Grande. You can hit your ball into Mexico, and it comes back into the United States. The beauty that comes with that, the natural landscape, 30-year-old oak trees — this is not a Walmart that I could just go reproduce on any other corner.”

Barnard, who voted for Trump, said he does not want to fight the Trump administration.

“We realize it’s a security issue. We are willing to work with them,” he said. “But we are not just going to hand over our land and say, ‘Here you go!’ ”

Thus far, the government has yet to approach the family about the land. If and when it does, Barnard plans to convey the cooperative relationship the club has developed with Border Patrol and immigration officials in the past two years.

When his family first took over the club, Barnard said, he would witness narcotics activity daily. There’s been a dramatic decrease in drug trafficking since the club hired a full-time security guard and cleared the river banks of weeds where drug runners hid. Border Patrol also uses the club’s boat ramp to launch patrol boats and protect the river.

“It’s not like if you build a wall your problem is gone,” Barnard said. “We need more boots on the ground. More boats, more sensors, more drones that would be more efficient and more productive.”

It remains an open question how much sympathy Trump would have for Barnard's situation — or that of any other private landowner standing in the way of Trump's wall.

As a developer, Trump has wielded the power of eminent domain to make way for his properties. In Scotland, he pursued compulsory purchase to force neighbors out of their homes for the Trump International Golf Links near Aberdeen. When that didn't work, he built a five-foot-tall wooden fence — then tried to make his neighbors pay for it.

Trump also famously tried seizing the property of an elderly Atlantic City widow to make way for a limousine parking lot for his hotel and casino. He has a consistent history supporting the use of eminent domain and praised the 2005 Supreme Court decision — denounced widely by conservatives — that said the government could force property owners to sell their land to make way for private economic developments that benefit the public.

“I happen to agree with it 100 percent,” Trump said during a 2005 Fox News interview. “If you have a person living in an area that’s not even necessarily a good area, and … government wants to build a tremendous economic development, where a lot of people are going to be put to work and … create thousands upon thousands of jobs and beautification and lots of other things, I think it happens to be good.”

Trump reiterated his support more recently, calling eminent domain “wonderful,” in a 2015 Fox News interview, when “you need a house in a certain location because you're going to build this massive development that's going to employ thousands of people.”