Mr. Manuel Rubio, Jr. of the IBWC was in his El Paso office shortly after 7:30
(his time) this morning phoning me with answers to my e-mailed questions of
yesterday.

He was very cordial and patient to explain everything, but some of his
explanations still contained a bit of hedging and lack of exactitude, as you
will see below:

First, he said that "for practical purposes" the monuments on the bridges mark
the boundary on the bridge structures. He said that US Customs and other
authorities would not go beyond the monuments on the bridge, but that the middle
of the river was the boundary on the ground per the treaties.

When I asked for further clarification of "for practical purposes," he explained
that the middle of the river was always going to be moving, and that the treaty
boundary moved with it, but that the Commission couldn't go out and adjust the
monument every year or two. That would be impractical, would cause confusion,
and would cause taxable private property to move between jurisdictions. For
that reason, the monuments on bridge structures are never moved once fixed.

I then asked if this meant that the monuments on the bridges are
"jurisdictional" boundaries by mutual agreement for practical purposes, but that
the actual breaks in sovereignty on the bridges are over the middle of the river
as changed by accretion. "No," he said, "we consider" the monument to mark the
break in sovereignty "on the bridge structure."

Obviously, this was getting deeper with every passing sentence!

I asked him if he was saying that there was a "vertical offset" in the boundary
between its location on the ground and its location on the bridge, which might
be some distance away. Before he could answer, I enunciated the theory that a
boundary is a vertical wall extending downward to the center of the earth and
upward to the margins of space--that possession of sovereignty on the ground
generates a territorial airspace above it, just as sovereignty on a coastline
generates a territorial sea.

Perhaps realizing that he was dealing with no amateur, Mr. Rubio seemed to
become a bit more frank. He said that, while the treaties do place the boundary
at the middle of the river, they also charge the international Commission with
the authority to survey and demarcate it. He explained that the practical
policy has always been that the "proponent" of a bridge (he who proposes to
build one) is instructed by the Commission that the boundary on the structure
will be and will ever remain over the middle of the river as of the time the
bridge is built. It is up to the proponent to design and build his bridge with
that point in mind [as it pertains to dividing costs and ownership between
international partners, etc.]. He said that the proponent actually sets the
monument on his bridge in accord with the Commission's instructions, and subject
to the Commission's inspection and approval. All of this is noted in each case
in the "minutes" of the Commission.

Obviously, there is no "vertical offset" at the time the bridge is built; and
Mr. Rubio seemed unwilling to concede the use of that term even after the river
had moved by accretion. The Commission just considers the boundary on the
ground and on the bridge to be in two different places. He said, "We just don't
know how else to handle it," [a direct quote].

I asked him if the treaties specifically authorize the permanence of
demarcations on bridges despite subsequent accretions of the river. He asked me
to send him my postal address by e-mail, and he would send me the printed text
of the treaty of 1970, which currently governs. Did I sense him hesitating to
go where my question took him?

Not willing, myself, to accept the notion of a vertical offset, but because Mr.
Rubio had been so nice, I tried diplomatically to suggest a possibility: If the
treaty charged the Commission with surveying and demarcating the boundary, then
established and accepted monuments might fix the boundary at a bridge,
subsequent accretions notwithstanding (in the same way that an imperfect but
accepted demarcation fixes a land boundary). Under this theory, I ventured,
perhaps the accreted land under the Mexican portion of a bridge might be
Mexican. To this, Mr. Rubio replied that if something happened, it would be a
"lawyers' field day." [For our friends whose native language is not English,
"field day" is idiom for a time of extraordinary pleasure and opportunity.]

Out of points to ponder, our conversation wound down, so I thanked Mr. Rubio. I
have sent him my postal address for the treaty text and will report in time.

So, most of my questions remain somewhat less than completely answered. I
suspect that the actual state of the boundary's exactitude is similarly
imperfect.

Lowell G. McManus
Leesville, Louisiana, USA