In declaring a national emergency to build a border wall last month, President Donald Trump described the move as the fastest path to construction — and Texas is one of the administration's top priorities for the next round of barrier building.

But as the U.S. Senate prepares to vote on the declaration — and Trump readies his veto pen — legal experts say that even if the president gets his way, a variety of legal issues could delay wall construction for years and even derail it entirely. Even under an emergency declaration, they say, a president doesn't have free rein to take land for a border wall — partly because, according to several experts, the declaration makes the legal questions surrounding land seizures even murkier.

Under normal circumstances, the federal government has extraordinary eminent domain powers. If it wants to seize property, landowners are virtually powerless to stop it. But several attorneys and academics who specialize in eminent domain law said that’s only if Congress specifically authorizes the condemnatio or the project that requires it.

“By trying to run around Congress’ authority … [Trump is] inadvertently jeopardizing his whole project,” said Texas-based eminent domain attorney Charles McFarland, who represented a border landowner facing condemnation for past wall construction.

The outcome of the political struggle in Washington — and the many lawsuits challenging the declaration — is particularly relevant for Texas border landowners.

The administration has declared the Rio Grande Valley, which has recently seen the highest number of unauthorized border crossings, as a priority for wall construction. Some of the first segments of Trump’s wall are already under construction there, paid for by funds Congress authorized last year. And unlike other border states, where the federal government already owns much of the border land, the vast majority of border property in Texas is privately owned, meaning the federal government will have to seize it before it can build more barriers there.

The U.S. House has already voted to nullify the emergency declaration, and its fate in the Senate is uncertain — but even if the upper chamber also votes to nullify it, Trump is widely expected to issue his first-ever veto.

But Ilya Somin, a law professor at George Mason University who specializes in eminent domain law, said that will be the first of many hurdles Trump must clear.

For one, he said, it’s uncertain if the statutes Trump cited in his emergency declaration actually allow him to spend money on wall construction.

Somin said that Section 2808 — a federal law Trump invoked in his declaration that allows for the diversion of military funds for construction in the event of a war or emergency — “specifically indicates that you can only spend the money in the case of a national emergency where it’s necessary to use the armed forces.

“Here, it’s clearly not necessary,” he said, but he acknowledged that the Trump administration may cite its recent deployment of the military to the border as evidence that the armed forces are required.

Still, even if Trump is authorized to spend money for wall construction, Somin said he doesn't believe Section 2808 authorizes the use of eminent domain because previous U.S. Supreme Court rulings say that power has to be authorized by Congress.

"So even if he can spend money, it doesn’t follow that he can use that money to condemn property,” Somin said, adding that the administration would then be limited to building the wall on land the federal government already owns.

Nick Laurent, an Austin-based eminent domain attorney representing several Texas border landowners facing condemnation for the wall construction already authorized for the Rio Grande Valley, agreed that it's unclear whether Trump can legally divert money from other parts of government to condemn land for a wall. Laurent said a 1952 ruling by the U.S. Supreme Court that barred President Harry Truman from seizing private property under an emergency declaration “will certainly come up as an issue.”

“It’s just another question in the big picture,” he said. “Even if money can be used for construction, can the government seize private land under the emergency declaration?”

Government lawyers may claim the executive branch already has congressional authorization to seize private land on the border, as they did in a recent condemnation case, said McFarland, who is advising the nonprofit Texas Civil Rights Project in condemnation lawsuits involving the wall. In the eminent domain lawsuit filed last year against a Rio Grande Valley landowner, U.S. Department of Justice attorneys cited a set of laws, including the Consolidated Appropriations Act of 2008, which sets no maximum mileage limits for barriers along the southwest border. In future condemnation cases, the administration may rely on the same set of laws to argue that it already has congressional authorization, according to McFarland.

While some eminent domain attorneys may argue the 2008 law isn’t a blank check to seize land for all kinds of border barriers, McFarland said congressional authority doesn’t have to be explicit — it can just be implied — so there’s a chance that the court will still side with the federal government.

“There’s enough smoke where a judge could say, ‘I see implied authority here,’” McFarland said.

In addition to proving its eminent domain authority, the federal government must also prove that the wall has a public benefit, said Dwight Merriam, a Connecticut-based eminent domain attorney. And he said declaring a national emergency doesn’t waive that requirement, which is a longstanding tenet of eminent domain law.

Demonstrating that there are alternatives that would be better and cheaper — like a “digital wall,” more Border Patrol agents or real-time drone surveillance — would pose a solid legal argument against it, he said.

Trying to build a wall using an emergency declaration also eliminates one of the government's most potent tools for seizing land, McFarland said.

More than a decade ago under the George W. Bush administration, the federal government seized private land along the U.S.-Mexico border and built roughly 700 miles of fencing using what's known as "quick takes," a reference to the Declaration of Taking Act, which Congress passed during the Great Depression to help stimulate the economy. The act allows the federal government to swiftly seize land to build projects, then compensate landowners later.

But quick takes also require specific congressional authorization, McFarland said.

Without Congress' authorization to do quick takes, McFarland said, land disputes would have to be resolved in court before the federal government could start wall construction. That process can take years, and McFarland said a long enough delay could ultimately kill Trump’s plans for a longer border wall — especially if Trump doesn't win re-election.

“The next administration is going to shut this down,” McFarland said. “2020 is a drop-dead date for this project. If you can dribble out the clock, you win.”

Roy Brandys, another Austin-based eminent domain attorney who works with Laurent, stressed that landowners who decide to fight condemnation must immediately site all the legal objections they plan to use in their challenge to the government's "right to take," or they will more than likely lose the chance to do it later. After the government first moves to condemn property, owners have 20 days to respond.

“You have to allege all of your defenses — all of your counter-claims, whatever it is you’re contesting — in the very first pleading you file,” he said. “So if I’m the government, I could file [a lawsuit to condemn property], and if the landowner didn’t know to bring up the issue of right to take in that first pleading, they could proceed.”

Politically speaking, Somin said Trump could come out on top even if he ends up getting blocked in the courts or delayed by a lengthy condemnation process.

“It might be that he’s biting himself in the ass in that the emergency declaration is unpopular,” Somin said. But “even if ultimately what happens is the courts stop it or it takes many months or years to build much of anything, he can at least tell his base he’s pushing on it. Whether that’s worth the political cost for him, I think the answer to that at this point is unclear.”