President Trump put the first concrete number on the miles of border he wants to fence off, saying “anywhere from 700 to 900 miles” need his border wall — and he said he wasn’t joking when he suggested erecting solar panels to help pay for construction.

“There is a very good chance we can do a solar wall,” the president told reporters Wednesday night aboard Air Force One en route to France.

During the campaign Mr. Trump said he wanted to see a wall across the 1,954-mile border with Mexico, but told reporters that he’s been convinced there are a number of areas that don’t need fencing because of natural barriers.

“But you’ll need anywhere from 700 to 900 miles,” he said.

Mr. Trump also agreed with border security experts who say the wall needs to allow visibility through to the Mexican side, as a safety precaution. The president said smugglers will throw heavy sacks of drugs up over the fence, which is a danger to Border Patrol agents.

“They hit you on the head with 60 pounds of stuff,” he said.

Rocks turn out to be an even bigger threat, with agents saying they regularly face attacks in which someone on the Mexican side will toss rocks and even small boulders over the fence at them. It’s so common that agents have dubbed such attacks “rockings.”

The Border Patrol has struggled with a policy to deal with rocking incidents, debating whether deadly force is an acceptable reply.

Customs and Border Protection, the agency that oversees the Border Patrol, is in the midst of evaluating proposals for the border wall, and has sought both concrete and non-concrete designs, specifically looking for versions that would allow visibility.

Congress took the first steps toward a down payment for the wall this week, with the House including $1.6 billion to build 60 miles of new barriers in Texas and to replace 14 miles of existing secondary fence in San Diego.

Those areas were deemed the highest priority by CBP.

Mr. Trump said both erecting new fencing and replacing obsolete old fencing are top priorities.

Some 352 miles of the border have a pedestrian fence, and another 300 miles have barriers that can stop most vehicles but allow foot traffic to cross easily.

Mr. Trump didn’t say whether his 700-900 mile projection was in addition to the current fencing, or a cumulative total.

CBP has said it’s in the middle of a study to determine what parts of the border need fencing. In a briefing last month, a top official said they’d ruled out 130 miles that had enough natural barriers.

That would suggest a far larger potential footprint than Mr. Trump is thinking, based on his comments this week.

Mr. Trump said a solar wall “would actually look good,” as well.

The president raised the possibility of solar panels on the wall as a way to help raise money to pay for construction earlier this year, drawing derision from some quarters. Indeed, the reporter who pressed him on it Wednesday insisted “you were joking about solar, right?”

“No, not joking, no,” Mr. Trump responded.

Sign up for Daily Newsletters Manage Newsletters

Copyright © 2020 The Washington Times, LLC. Click here for reprint permission.