Cutting through the vertical bollards in Trump's "virtually impenetrable" wall takes mere minutes, using a $100 reciprocating saw and "extreme metal cutting" blades that sell for $10-15; once cut, the length of the bollards provides leverage to wall-cutters so they can be easily bent to allow a person to pass through them, and afterwards, the bollards can be replaced and cemented with easy-to-cut putty that border patrol officers often mistake for official repair welds (these welds are only slightly harder to cut through than the putty).
The gaps between the bollards also lend themselves to being defeated by cheap ladders made from rebar; once people have gone over the wall, the ladder can be passed between the bollards for use on inner, secondary walls.
In response, the Customs and Border Protection service have developed sophisticated countermeasures: they kick the bollards to see if they'll bend.
In defense of the wall design -- budgeted for more than $21b and likely to come in significantly at significantly higher total prices -- CBP says that the cut bollards only allow one person at a time through, while older barriers allowed several people through at once. However, it's more accurate to say that an individual cut bollard only admits one person, but people smugglers can cut through very large numbers of these bollards in very short time for very small sums of money.
The wall was paid for in part by diverting money from budgets allocated for schools for the children of active-duty American soldiers.
As he left the White House for Andrews Air Force Base en route to New York on Saturday, Trump was asked if he was concerned about smugglers cutting through the new wall.
“I haven’t heard that,” Trump said. “We have a very powerful wall. But no matter how powerful, you can cut through anything, in all fairness. But we have a lot of people watching. You know cutting, cutting is one thing, but it’s easily fixed. One of the reasons we did it the way we did it, it’s very easily fixed. You put the chunk back in.”
Smugglers are sawing through new sections of Trump’s border wall [Nick Miroff/Washington Post]