President Donald Trump's border wall is moving, at least figuratively.

Bloomberg News reported that the Department of Homeland Security will this week begin soliciting construction bids for a 30-foot concrete barrier and "other designs."

Congress is also gearing up to consider the wall, funds for which were sought Thursday in Trump's budget request. If the president's experience with Congress on health care is any guide, "other designs" may turn out to be a euphemism for the next phase of his political education.

Some congressional Republicans seem even less enamored of a wall than of grappling with the complexities and trade-offs of health-care policy. "I've never thought we needed a 2,000-mile wall. We have to use technology," Senate Homeland Security Chairman Ron Johnson told Bloomberg. "We have to use boots on the ground in some areas."

When the Texas Tribune surveyed the Texas delegation about a wall in December, many representatives failed to respond, forgoing the opportunity to display their ardor for Trump's signature initiative. But some who did were unintentionally funny.

A spokeswoman for Republican Rep. Pete Sessions responded that Sessions considers Trump's fulminating about a wall an "analogy" for how Trump will "strengthen border security, protect our sovereignty and maintain our nation's rule of law."

House Homeland Security Chairman Michael McCaul of Texas was far more literal in a Fox News op-ed article he published Dec. 2. It was titled, "Yes, we will build a wall, put Mexico on a 'payment plan' and enforce the law."

When his office was subsequently contacted by the Tribune, however, the McCaul camp was suspiciously low energy. "When asked by the Tribune if that meant he supported a contiguous wall along the entire border, a spokeswoman declined to comment," the Tribune reported.

Rep. Roger Williams told the Tribune he supports "a wall where we can build," while Rep. Randy Weber asked: "Do we need to build a wall the entire way? That's a discussion we'll have."

Indeed, the Tribune reported, "none of the 38-member Texas delegation offered full-throated support of a complete border wall."

One reason for a lack of enthusiasm is a strong doubt that all of the terrain along the border can reasonably support a wall. As Fox News reported: The southern border between the U.S. and Mexico is made up of wetlands, grasslands, desert, rivers, mountains and forests — all of which could pose pitfalls for builders.

Swaths of the area also feature a thick layer of loose sediment — like dirt, sand and soil — on top. Some spots are packed with hydrophilic clay soil, which swells, moves and could destroy the foundation.

Another reason is that much of that land belongs not to the government but to residents of Texas, which has the longest stretch of border with Mexico. Many Texans are not eager to relinquish it.

The government used eminent domain to acquire borderlands for previous fence building. More will be necessary. One family received a letter offering them $2,900 for 1.2 acres near the Rio Grande. "We don't want this wall — the town is pretty much united on that," Yvette Salinas told the Texas Observer. "But we don't want to get sued by the U.S. government either."

It turns out that borders, much like health insurance, are complicated. Perhaps Congress will encourage Trump to settle for a symbolic barrier and lots of technology doing the real work.

If not, Republicans may move from voting to take some Americans' health insurance away to voting to take others' land away.

Francis Wilkinson (fwilkinson1@bloomberg.net) writes editorials on politics and U.S. domestic policy for Bloomberg View.