The border wall became a powerful and controversial symbol of Donald Trump’s candidacy, and now his presidency, but it wasn’t that long ago that the idea of a wall was embraced by both parties as a reasonable and common-sense measure to address illegal immigration.

For years, most Americans didn’t give the project a second thought. About one quarter of the border already features a physical barrier constructed in the 1990s. But now that Trump’s contribution is about to get underway, serious obstacles (no pun intended) may very well keep the “big, beautiful wall” from ever living up to the image engrained into the American consciousness.

In the 1990s, Bill Clinton asserted, “We are a nation of immigrants. But we are also a nation of laws. It is wrong and ultimately self-defeating for a nation of immigrants to permit the kind of abuse of our immigration laws we have seen in recent years, and we must do more to stop it.” Sounds a lot like President Trump, doesn’t it? And at the time, both Republicans and Democrats supported the idea.

In 2006, the Secure Fence Act moved through both houses of Congress to be signed into law by George W. Bush. The act called for several hundred miles of triple-fencing. Neither the Clinton- nor Bush-era border plans faced significant opposition, but as hundreds of thousands of illegal aliens became millions, any semblance of bipartisanship on the issue came to end.

The real political chasm developed when Democrats recognized the tremendous benefit of turning immigrants (and their children) into a long-term constituency. At the same time, establishment Republicans realized the value of cheap labor and certain other elements of the conservative coalition fell in line.

Democrats moved even further to the Left by embracing amnesty and characterizing any attempt to limit immigration (legal or illegal) as antithetical to the values of our country. They then brought out the race card against anyone who opposed amnesty and turned illegal immigrants into victims deserving of constitutional protections and government services.

Characteristically, Republicans had no response other than tripping over themselves to reach across the aisle while parroting the phrase “comprehensive immigration reform.” That is, until Donald Trump made the wall a cornerstone of his presidential candidacy.

But to go from the bold idea of a wall to the actual construction of it may be a considerable challenge — we are talking about the federal government, after all. But this doesn’t mean giving into the Democrats.

Some of these challenges include the public’s high expectations, the geography of the Rio Grande, the reality of funding (don’t expect Mexico to pay up), and the necessity to acquire private property to build portions of the wall. To address many of these issues, Trump’s plan even calls for additional attorneys to litigate a wide range of logistical issues.

As for the problem of building along a river that traverses hundreds of miles of the U.S.-Mexico border, the Rio Grande itself has been a natural barrier to illegal immigration for years. But the Trump administration wants to build there anyway. Texas Republican Gov. Greg Abbott opposes this idea, as well as Trump’s plan to build the wall through the Big Bend National Park. Thus, the wall is becoming one of those government projects (like prisons and waste disposal facilities) that Americans overwhelmingly support but don’t want in their own backyards. And that’s a real problem.

Looking back, one wonders if Trump over-sold the wall. Had Candidate Trump simply pushed for sections of it to complement a broad range of border-enforcement measures, many of the current problems could have been avoided. But now everyone is expecting something “big and beautiful,” even if they don’t support it.

What’s interesting is that illegal immigration is already dropping precipitously, but not because of any specific action. The mere fact of Trump’s stand on the issue has resulted in thousands of illegals leaving the country on their own and has stopped even more from trying in the first place.

The good news for conservatives is that President Trump seems to be tackling immigration from multiple angles. The wall by itself won’t completely stop the flow of illegal aliens and drug dealers, but a more multi-faceted approach will help.

At the same time, Trump made the wall such a critical component of his campaign that it’s come to symbolize his presidency. In other words, Trump must not only build this wall to protect our southern border; he must build it if he hopes to have a successful presidency.