I don’t know what the length and height of a fence should be but where a fence does exist it works. Also about who will pay for it. If the Feds would remove the prohibitions to building any fence it may have a lot of private funding by the property owners not federal funding.
We are currently spending a lot of federal and state money guarding and defending a border that is not even well marked in places.
Punishing the employers would help as would punishing the trespassers. Not just only deporting them.
A fence is impractical solution to any country with thousands of miles of border. A better solution is to remove the magnet which attracts illegals. The magnet is jobs and welfare. Russia has a longer border but no one dares enter illegally. Very harsh punishment!
Even a small country like Israel can not build airtight fence. There are hundreds of tunnels under the fence.
And then there are 5 million illegals who entered legally as tourists, students, in transit passengers, etc. who never left. Fence would do absolutely nothing for those 5 million.
If we had a few Billion surplus sitting in the US Treasury, I would absolutely have nothing against a 2000 mile fence on the southern border. Instead we have annual deficits of Half a Trillion every year.