<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by RichG:
"The Border Patrol, as the mobile uniformed branch of the Immigration and Naturalization Service, has as its mission the detection and prevention of smuggling and illegal entry of aliens into the United States, with primary responsibility between the Ports-of-Entry."</font>
I'm not quite sure what the point of your post is, but let me clarify my previous statement. At some domestic US airports that are near the border with Mexico, you must pass through a checkpoint of sorts before boarding. These checkpoints are run by uniformed Border Patrol officers. It's not an immigration checkpoint per se, but a check for illegal aliens, since at that point, everyone present is either already legally admitted to the US (or born here and has never left), or is illegally present. That is, they're looking to round up illegal aliens, not determine whether or not to admit you.
Although the Border Patrol is part of INS, these checkpoints are nothing like the ones that you go through when arriving in the US from another country. Those checkpoints are run by immigration inspectors, not Border Patrol officers, and they
do serve to determine who is allowed in and who isn't.