As President Donald Trump appeals to Congress to reach an agreement on border security, and the bipartisan conference committee is scheduled to hear from experts later this week, prospects for a deal seem weak.

Democrats continue to call the “wall” both “racist” and “immoral,” and President Trump is threatening to use his emergency powers — under the Constitution and the law — to divert funding to construct a barrier at the border.

But in theory, an agreement should be possible, because the changes the Trump administration seeks at the border are not radical, and because Democrats have agreed in the past to similar physical barriers to what Trump is proposing.

To understand how close the two sides really are, it is first necessary to understand the basic facts about the existing border barriers, reviewed in comprehensive detail recently by USA Today and the Wall Street Journal.

The U.S-Mexico border is about 2,000 miles long.

The border includes natural barriers such as mountains, and stretches of the Rio Grande where a barrier would be unhelpful. For these areas, high-tech monitoring will suffice.

President Trump only wants to build a barrier on the rest of the border — some 700 to 1000 miles, or 30% to 50%.

The wall “fight” is over 215 miles (10%) of the border, of which only 100 miles (5%) will be a new barrier.

Currently, there are about 650 miles of existing barrier. Most of it runs along the states of California, Arizona, and New Mexico, with only short stretches in Texas. Of that 650 miles, only half is “pedestrian” fencing; the rest is vehicle fencing, which people can climb over or under fairly easily, though much of it is in hostile desert areas.

Of the existing “pedestrian” barrier, some consists of wire-mesh fence, which is often easily cut through; and some is “landing mat” fencing, which is relatively easy to climb over and difficult for Border Patrol agents to see through.

President Trump’s proposals for the border have changed several times, and the public has yet to see specifics. But the general outline is as follows:

Replace weak pedestrian barriers with steel bollard fence, or wall;

convert some or all vehicle barriers to pedestrian barriers, using steel bollard fence, or wall;

build a few new barriers, using steel bollard fencing, in areas where gaps allow illegal crossings;

use new technology to monitor the border and to stop smuggling at ports of entry;

hire thousands of new law enforcement officers; and

change laws to encourage asylum-seekers to use ports of entry rather than crossing illegally.

Democrats say they will never fund a “wall.” But according to the Journal, Speaker of the House Nancy Pelosi (D-CA) has agreed, in principle, to fund some new vehicle fencing. And they have agreed to bollard fencing in the past.

Both sides agree on the need for new technology. Both sides agree that new law enforcement officers are needed — though they disagree on precisely how many.

The only outstanding questions are whether Democrats will agree to fund the construction of new steel bollard fences — whether to fill gaps, to replace vehicle barriers, or to replace weaker pedestrian barriers.

A deal should be possible. All that stands in the way is politics — specifically, the fervent desire of Democrats to deny President Trump a political win on his most important pledge.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.