SAN FRANCISCO (KGO) --Groups based in the Bay Area say they are ready, willing, and planning to stop President Donald Trump's effort to build a border wall.
Mr. Trump made good on that campaign promise Tuesday, signing an executive order to jumpstart the construction of that wall.
The President told ABC World News Anchor David Muir that he expects Mexico to pay for that wall. Activists say that won't be allowed to happen.
"We do have allies in Congress who are fighting for the immigrant community and have the ability and the opportunity to put pressure and put roadblocks in the process to make sure that the border wall isn't built," Siren Policy & Advocacy Director Priya Murthy said.
Leverage may come from blocking the funds to build it if Mexico doesn't pay for it. The cost, by some estimates, could top $10 billion.
However, there are other potential obstacles or delays.
The border wall will require environmental reviews according to the former deputy general counsel of the EPA, now at Santa Clara University School of Law.
"Given that this is a massive project that will take years to complete, it would be even more important to engage in a considered review of both endangered species impact and environmental impacts generally," Professor Tseming Yang told ABC7 News.
Such reviews could delay construction up to a year, or longer if challenged by a lawsuit.
The U.S. and Mexico also have long-standing treaties that could require bilateral approval of a physical change to the border.
Another obstacle could be a 75-mile stretch along the Arizona border that is controlled by a Native American tribe. The tribe has indicated it won't allow a wall on its land.
"The talk of a wall is more painful here in this country because the wall is also a symbol of you're not welcome here, and that's really the painful reality that we're dealing with," said Father Jon Pedigo with the Diocese of San Jose.