President Trump's must-have border wall is a long ways off, according to sources who described the construction process as fraught with bureaucratic and legal obstacles that are likely to delay the high-profile project even if the funding is there.

A source close to the White House told the Washington Examiner that Trump is prepared to go to the mat next month to ensure the multi-billion dollar spending package passed by the House before August recess clears the Senate without a substantial reduction to the $1.57 billion in funding for wall construction.

"Last I heard, he was still open to shutting the government down to get money for border security," the source said, adding that Trump "seemed optimistic that [a government shutdown] won't actually be necessary."

In a rare and contentious briefing last month, senior Trump adviser Stephen Miller said Senate Democrats would pay "a steep political price" and "cause an uproar from the American people" if they try to strip the upcoming funding bill of money for the border wall.

But before any federal funds are used to build a barrier along the U.S.-Mexico border, the Department of Homeland Security must decide what kind of structure – solar, concrete, steel, etc. – will meet the president's request for a "big, beautiful wall" that withstands severe weather and prevents intruders from climbing it, digging beneath it, or tossing "large sacks of drugs over [it]," as Trump recently said.

Few companies that submitted architectural renderings and cost estimates to Customs and Border Protection this summer for the chance to construct wall prototypes in San Diego, Calif. have heard back from the agency about whether their bid was accepted or when construction will begin.

"This was supposed to be already completed back in July and there's been several delays," Ralph DeSio, a CBP public relations officer in Southern California, told the Washington Examiner. "The money to do the prototypes is already there but there's been protests and a three-month delay so far."

Another CBP official said the agency has been closely monitoring a lawsuit filed by the nonprofit Center for Biological Diversity, which could cause further delays if the government fails to respond by the first week of September.

The lawsuit alleges that DHS sidestepped a section of the National Environmental Policy Act that would have required the agency to produce an environmental impact study on the border wall.

"The Otay Mesa area, where the presumed Border Wall prototype construction will take place, is of high environmental and natural resources value," states the lawsuit, which was filed in June at the U.S. District Court for the Southern District of California.

Two bidders on the border wall project also filed protests against CBP after their submissions were rejected by the agency, which plans to approve the construction of "four to eight prototypes," according to previous statements. Those bid protests must be reviewed by the Government Accountability Office within 100 days of filing, meaning prototype construction is unlikely to begin until the late fall or early winter.

"I expect things to be in motion before winter hits. That's my hope," DeSio said, noting that his field office has turned its attention to more pressing issues in the interim. "It's been eating up a lot of our local time to get ready for this and it never materialized, so we're just moving on."

It is still unclear how many companies that responded to the government's solicitation for border wall designs have heard from CBP since their submissions were accepted.

The chief executive of one Texas-based concrete manufacturer, who requested anonymity to avoid jeopardizing the company's chance of winning a contract, said several attempts to get an update from CBP were unsuccessful.

"I made a few calls and no one could answer my questions. If they already picked everyone [for prototype construction], they should tell the rest of us so we can get on with it," the source said.

"We haven't received anything official saying, ‘Oh, it's been delayed,'" said Dennis O'Leary, CEO of DarkPulse Technologies, an Arizona-based company that claims it was selected for the prototype construction phase.

O'Leary told the Washington Examiner that his company, which specializes in fiber optic sensing, has sent personnel to the site where the wall prototypes are expected to be built to take soil samples and complete other "engineering groundwork."

But he still has no idea when they will be invited to San Diego to begin construction.

"We're just sort of waiting to hear what our date is going to be," he explained. "We're kind of reserving staff in case we do have to be on site at a moment's notice, so it has impacted us somewhat. We're basically paying additional staff that we wouldn't normally have."

In addition to a start date, O'Leary said CBP has not clarified whether each vendor will need to supply their own equipment for prototype construction and on-site security.

"I know there's some support from local law enforcement, but I couldn't tell you if we'll be responsible for site access and entry," he said.

It is also unclear whether the administration plans to begin construction on any part of a Southwest border wall before the prototypes have been completed and a design for the structure has been chosen.

CBP has said the wall must be 25 to 50-feet tall and made of see-through material or solid concrete that would take an hour to cut through with a "sledgehammer, car jack, pickaxe, chisel, battery operated impact tools, battery operated cutting tools, Oxy/acetylene torch or other similar hand-held tools."

A White House official did not respond to questions about the prototype project, including whether Trump has personally reviewed any of the 200-plus design submissions that CBP received.